Open Access Published by De Gruyter July 22, 2017

Chemical and pharmacological research on the plants from genus Ajuga

Xia Qing, Hui-Min Yan, Zhi-Yu Ni, Christopher J. Vavricka, Man-Li Zhang, Qing-Wen Shi, Yu-Cheng Gu and Hiromasa Kiyota

Abstract

The genus Ajuga, a member of the Lamiaceae family, is comprised of more than 300 species of annual and perennial herbaceous flowering plants mainly distributed throughout the temperate regions of Asia, Europe, Australia, North America and Africa. These plants are used as folk medicines effective for rheumatic fevers, dysentery, malaria, hypertension, diabetes and gastrointestinal disorders, as well as anthelmintic, astringent, febrifuge diuretic, antifungal and anti-inflammatory agents. A variety of constituents has been isolated from these plants. This review summarizes the phytochemical progress of the genus Ajuga and lists the compounds isolated up to 2014.

Introduction

The genus Ajuga, a member of the Lamiaceae family, is comprised of more than 300 species of annual and perennial herbaceous flowering plants mainly distributed throughout the temperate regions of Asia, Europe, Australia, North America and Africa. These species have been used as common house plants and are called bugle or bugleweed. They are mainly characterized by the color and shape of the flower. For example, the flower of Ajuga reptans is somewhat tall and blue, while that of Ajuga decumbens is short and purple. Many of these plants are of medicinal importance and are traditionally used as remedies for rheumatic fevers, dysentery, malaria, hypertension, diabetes and gastrointestinal disorders, as well as anthelmintic, astringent, febrifuge diuretic, antifungal and anti-inflammatory agents [1]. The genus Ajuga has attracted attention since the report in 1976 that Ajuga remota grown in Kenya is not attacked by African armyworms and contains three moderately strong antifeedants [2]. Since then, reports of the isolation of neoclerodanes and phytoecdysteroids, as the insect allelochemicals responsible for antifeedant activity from this genus, have appeared [3]. Several species of this genus have been chemically studied and a series of bioactive metabolites, including phytoecdysteroids, diterpenoids and iridoids have been isolated and characterized. Biological investigations demonstrate that some of these compounds display antibacterial [4], antifungal [5], antiplasmodial [6], cytotoxic, antitumor promoting [7], vasoconstricting [8], insect molting inhibitory, insect antifeeding [9] and enzyme-inhibitory [10] activities. This review summarizes phytochemical progress of the genus Ajuga covering the literature up to 2014. In addition, some biological activities of compounds obtained from this genus are also listed.

Chemical constituents

There have been many phytochemical investigations on the isolation of constituents from the Ajuga genus. This has resulted in the isolation and characterization of a series of secondary metabolites, including phytoecdysteroids, sesquiterpenoids, diterpenoids, triterpenoids, iridoids, withanolides and some other compounds. Phytoecdysteroids, the characteristic components of Ajuga plants, are discussed first.

Steroids

Phytoecdysteroids (Table 1, Figure 1)

Phytoecdysteroids are widespread in the genus Ajuga. These compounds display interesting physiological activities such as insect molting activity and other hormonal functions involving regeneration, metamorphosis, reproduction and differentiation in all arthropods. These compounds play important roles for defense against phytophagous insects. They also display antiulcer, antirheumatic, insulin regulation and diuretic or tonic activities in mammals [34]. Some of the successful applications of plants in folk medicine can be explained by the occurrence of phytoecdysteroids.

Table 1

Steroids 1: Phytoecdysteroids.

No. Name Source Part Ref.
1 Cyasterone A. decumbens whole plant [11]
A. turkestanica leaf [12]
A. iva aerial part [13], [14], [15]
A. chia leaf, stem [16]
A. chamaepitys whole plant [17]
A. multiflora aerial part [18]
A. taiwanensis whole plant [19]
A. nipponensis aerial part [20]
A. macrosperma var. breviflora root [21]
2 Ecdysterone A. decumbens whole plant [11]
A. nipponensis whole plant [11], [22]
A. turkestanica leaf [12]
A. iva aerial part [13], [14], [15]
A. chamaepitys whole plant [17]
A. multiflora aerial part [18]
A. macrosperma var. breviflora root [21]
A. reptans whole plant [23], [24], [25]
A. remota leaf, root [26]
3 Ajugalactone A. reptans whole plant [25]
A. turkestanica root [27]
4 22-Acetylcyasterone A. turkestanica root [28]
5 Turkesterone A. turkestanica root [29]
6 Ajugasterone A A. nipponensis whole plant [22]
A. reptans whole plant [23], [25]
7 Ajugasterone B A. reptans whole plant [25]
A. turkestanica root [29]
A. iva whole plant [30]
8 Ajugasterone C A. nipponensis aerial part [20]
A. japonica leaf [31]
9 Ajugasterone D A. nipponensis whole plant [22]
10 Stachysterone D A. nipponensis whole plant [22]
11 Makisterone A A. iva whole plant [14], [32]
A. macrosperma var. breviflora root [21]
12 29-Norcyasterone A. reptans whole plant [23], [24], [25]
13 29-Norsengosterone A. reptans whole plant [23], [24], [25]
14 2-Acetyl-29-norcyasterone A. reptans whole plant [33]
15 3-Acetyl-29-norcyasterone A. reptans whole plant [33]
16 Sengosterone A. reptans whole plant [25]
17 22-Dehydro-12-hydroxycyasterone A. reptans var. atropurperea aerial part [34]
18 22-Dehydro-12-hydroxysengosterone A. reptans var. atropurperea aerial part [34]
19 22-Dehydro-12-hydroxy-29-nor-cyasterone A. reptans var. atropurperea aerial part [34]
20 22-Dehydro-12-hydroxy-29-nor-sengosterone A. reptans var. atropurperea aerial part [34]
21 Reptansterone A. reptans var. atropurperea root [35]
22 28-epi-Sengosterone A. reptans var. atropurperea root [35]
23 5,29-Dihydroxycapitasterone A. reptans var. atropurperea root [35]
24 2-Dehydroajugalactone A. reptans var. atropurperea root [35]
25 3-Dehydroajugalactone A. reptans var. atropurperea root [35]
26 Ponasterone A A. remota leaf, root [26]
27 24,28-Dehydromakisterone A A. iva whole plant [14]
28 22-Oxocyasterone A. iva whole plant aerial [14]
22-Dehydrocyasterone A. nipponensis part [20]
29 24,25-Dehydroprecyasterone A. iva whole plant [14]
A. reptans var. reptans whole plant [36]
30 20-Hydroxyecdysone 22-acetate A. nipponensis aerial part [20]
A. reptans whole plant [37]
31 20-Hydroxyecdysone 25-acetate (Viticosterone E) A. reptans whole plant [37]
32 Ajusterone A. pseudoiva leaf [38]
33 Ajugalide-E A. taiwanensis whole plant [19]
34 Isocyasterone A. taiwanensis whole plant [19]
35 24-Hydroxycyasterone A. iva whole plant [30]
36 22-Dehydrocyasterone 2-glucopyranoside A. nipponensis aerial part [20]
37 Ajugacetalsterone A A. nipponensis aerial part [20]
38 Ajugacetalsterone B A. nipponensis aerial part [20]
39 Ajugacetalsterone C A. macrosperma var. breviflora root [21]
40 Ajugacetalsterone D A. macrosperma var. breviflora root [21]
41 Breviflorasterone A. macrosperma var. breviflora root [21]
A. reptans var. reptans whole plant [36]
42 20-Hydroxyecdysone 2-acetate A. macrosperma var. breviflora root [21]
43 20-Hydroxyecdysone 3-acetate A. macrosperma var. breviflora root [21]
44 Reptanslactone A A. reptans var. reptans whole plant [36]
45 Reptanslactone B A. reptans var. reptans whole plant [36]
46 Sendreisterone A. reptans var. reptans whole plant [36]
Figure 1 Steroids 1: Phytoecdysteroids.

Figure 1

Steroids 1: Phytoecdysteroids.

Compounds 1 and 2 are usually the most abundant phytoecdysones in the genus Ajuga, and they were reported in A. decumbens, Ajuga incisa, Ajuga turkestanica, Ajuga iva, Ajuga nipponensis, Ajuga chia, Ajuga chamaepitys and Ajuga multiflora [11], [12], [13], [16], [17], [18]. Compound 36 was reported as a 2-O-glucopyranoside [20]. Phytoecdysteroids bearing a γ-lactone ring at various positions, 41, 44 and 45, were also isolated [21], [36]. Derivatives with a δ-lactone ring, 3, 21, 2325, 29, 37, and 46 were reported as well [14], [25], [27], [35], [36]. In addition, the reduced forms, 37 and 46 with a THP ring, and 38 and 40 with a THF ring, were isolated as acetals or hemiacetals [20], [21], [36]. Two other similar compounds with a THF ring 9 and 10, are biosynthesized from precursors via intramolecular hydration [22]. In addition, ajugacetalsterone C (39) has a rare 6,8-dioxabicyclo[3.2.1]oct-2-ene structure presumably formed by an intramolecular acetalization [21]. Fujimoto and co-workers summarized biosynthesis of ecdysteroids as well as sterols in Ajuga hairy root in detail [39].

Withanolides (Table 2, Figure 2)

Withanolides are characteristic of Solanaceous plants, though there are rare reports on their isolation from other families. In 1999, Khan and co-workers isolated a new withanolide 47 from Ajuga parvifora. This is the first report of naturally occurring withanolides in Lamiaceae [40]. In subsequent studies on the chemical constituents of A. parvifora, the same research group obtained a series of new withanolides 48–56, along with known 57 [41], [42], [43], [44], [45].

Table 2

Steroids 2: Withanolides.

No. Name Source Part Ref.
47 Ajugin A. parviflora whole plant [40]
48 Ajugin A A. parviflora whole plant [41]
49 Ajugin B A. parviflora whole plant [41]
50 Ajugin C A. parviflora whole plant [42]
51 Ajugin D A. parviflora whole plant [42]
52 Ajugin E A. parviflora whole plant [43]
53 Ajugin F A. parviflora whole plant [43]
54 3,14,17,20,28-Pentahydroxy-1-oxo-(20R,22R)-witha-5,24-dienolide A. parviflora whole plant [44]
55 3,17,20-Trihydroxy-1-oxo-(20S,22R)-witha-5,14,24-trienolide A. parviflora whole plant [45]
56 28-Hydroxy-14,20-epoxy-1-oxo-(22R)-witha-2,5,24-trienolide A. parviflora whole plant [45]
57 Coagulin-J A. parviflora whole plant [44]
58 Bracteosin A A. bracteosa whole plant [46]
59 Bracteosin B A. bracteosa whole plant [46]
60 Bracteosin C A. bracteosa whole plant [46]
Figure 2 Steroids 2: Withanolides.

Figure 2

Steroids 2: Withanolides.

Other steroids (Table 3, Figure 3)

Compounds 61 and 67, two C29 monohydroxy sterols, were isolated from A. reptans and their structures were elucidated by spectral methods [47]. From the aerial parts of Ajuga salicifolia, Akbay and co-workers isolated one new stigmastane-type sterol 72 and eight new sterol glycosides 70, 71, 73–78 [53], [54]. The whole plant of Ajuga relicta afforded two new steroids 79, 80, as well as two known compounds 61, 68 [49]. A steroidal glucopyranoside 64 was isolated from A. chamaepitys ssp. laevigata [51].

Table 3

Steroids 3: other steroids.

No. Name Source Part Ref.
61 Clerosterol A. reptans whole plant [47]
A. pseudoiva leaf [48]
A. relicta whole plant [49]
62 Clerosterol 3β-O-(β-D-glucopyranoside) A. pseudoiva leaf [50]
63 Mighavide (3-O-Butanoylclerosterol) A. pseudoiva leaf [48], [50]
64 3-O-β-D-Glucopyranosyl-stigmasta-5,25-diene A. chamaepitys ssp. laevigata whole plant [51]
65 Stigmasterol A. taiwanensis whole plant [19]
66 Stigmasterol 3-O-β-D-glucopyranoside A. taiwanensis whole plant [19]
67 22,23-Didehydroclerosterol A. reptans whole plant [47]
68 β-sitosterol A. relicta whole plant [49]
A. taiwanensis whole plant [19]
69 β-sitosterol 3-O-β-D-glucopyranoside A. decumbens whole plant [52]
70 Ajugasalicioside A A. salicifolia aerial part [53]
71 Ajugasalicioside B A. salicifolia aerial part [53]
72 Ajugasalicigenin A. salicifolia aerial part [54]
73 Ajugasalicioside C A. salicifolia aerial part [53]
74 Ajugasalicioside D A. salicifolia aerial part [53]
75 Ajugasalicioside E A. salicifolia aerial part [53]
76 Ajugasalicioside F A. salicifolia aerial part [54]
77 Ajugasalicioside G A. salicifolia aerial part [54]
78 Ajugasalicioside H A. salicifolia aerial part [54]
79 (24S)-24-Ethyl-11α-hydroxycholesta-5,25-dien-1-one A. relicta whole plant [49]
80 (24S)-24-Ethyl-7α-hydroxycholesta-5,25-dien-3-one A. relicta whole plant [49]
81 Ergosterol 5,8-endoperoxide A. remota aerial part [55]
Figure 3 Steroids 3: other steroids.

Figure 3

Steroids 3: other steroids.

Triterpenoids (Table 4, Figure 4)

In 1997, two lupan triterpenoids 82 and 83 were isolated from the aerial parts of Ajuga macrosperma [56]. Oleananes 84 and 85 were two known triterpenoids isolated from A. relicta [49]. From A. chamaepitys ssp. laevigata, two ursanes and one oleanane 86–88 were isolated [51].

Table 4

Triterpenoids.

No. Name Source Part Ref.
82 Betulinic acid A. macrosperma aerial part [56]
83 3-epi-Betulinic acid A. macrosperma aerial part [56]
84 Oleanolic acid A. relicta whole plant [49]
85 3-O-Acetyloleanolic acid A. relicta whole plant [49]
86 α-Amyrin A. chamaepitys ssp. laevigata whole plant [51]
87 β-Amyrin A. chamaepitys ssp. laevigata whole plant [51]
88 Ursolic acid A. chamaepitys ssp. laevigata whole plant [51]
Figure 4 Triterpenoids.

Figure 4

Triterpenoids.

Diterpenoids (Table 5, Figure 5)

Ajuga species are rich in diterpenoids. With respect to the carbocyclic skeleton, Ajuga diterpenoids roughly belong to two groups: neoclerodane and abietane types.

Table 5

Diterpenoids.

No. Name Source Part Ref.
89 Ajugarin I A. remota leaf [2]
A. nipponensis aerial part [57]
A. parviflora aerial part [58]
A. decumbens whole plant [59]
90 Ajugarin II A. remota leaf [2]
A. parviflora aerial part [58]
91 Ajugarin III A. remota leaf [2]
92 Ajugarin IV A. remota leaf [60]
A. ciliata var. villosior aerial part [61]
93 Ajugarin V A. remota leaf [62]
94 Clerodin A. remota

leaf [63]
A. bracteosa aerial part [64]
95 Dihydroclerodin A. parviflora aerial part [58]
A. bracteosa whole plant [46], [64]
A. remota aerial part [65]
96 Ajugareptansin A. reptans aerial part [66], [67], [68]
97 Ajugareptansone A A. reptans whole plant [69], [70]
98 Ajugareptansone B A. reptans whole plant [69]
99 Ivain I A. iva whole plant [71]
100 Ivain II A. iva whole plant [71]
A. bracteosa aerial part [64]
101 Ivain III A. iva whole plant [71]
102 Ivain IV A. iva whole plant [71]
103 Ajugapitin (Clerodendrin D) A. chamaepitys whole plant [72], [73]
A. australis aerial part [74]
A. decumbens leaf [75]
A. remota aerial part [65]
A. turkestanica aerial part [76]
104 14,15-Dihydroajugapitin A. chamaepitys whole plant [72], [73]
A. pseudoiva leaf [77], [78]
A. bracteosa whole plant [46], [64], [79]
A. remota aerial part [65]
105 Chamaepitin A. chamaepitys whole plant [80]
A. turkestanica aerial part [76]
106 Ajugamarin A. nipponensis leaf [81], [82], [83]
A. decumbens whole plant [75], [84], [85], [86]
A. ciliata whole plant [87]
107 Dihydroajugamarin A. nipponensis leaf [81]
A. decumbens leaf [75]
108 Ajugamarin chlorohydrin A. nipponensis leaf [81]
A. ciliata whole plant [87]
109 2-Acetylivain I A. pseudoiva whole plant [77]
110 Ajugamarin A2 A. decumbens whole plant [88]
A. nipponensis aerial part [83]
A. ciliata whole plant [87]
111 Ajugamarin B1 A. ciliata whole plant [87]
112 Ajugamarin B2 A. nipponensis aerial part [57], [83]
A. decumbens whole plant [88]
113 Ajugamarin B3 A. nipponensis aerial part [57]
114 Ajugamarin B4 A. ciliata var. villosior aerial part [61]
115 Ajugamarin B5 A. ciliata var. villosior aerial part [61]
116 Ajugamarin C1 A. nipponensis aerial part [57]
A. taiwanensis whole plant [89]
A. ciliata whole plant [90]
117 Ajugamarin D1 A. nipponensis aerial part [57]
118 Ajugamarin E1 A. ciliata var. villosior aerial part [61]
119 Ajugamarin E2 A. ciliata var. villosior aerial part [61]
120 Ajugamarin E3 A. ciliata var. villosior aerial part [61]
121 Ajugamarin F1 A. ciliata var. villosior aerial part [61]
122 Ajugamarin F2 A. ciliata var. villosior aerial part [61]
123 Ajugamarin F3 A. ciliata var. villosior aerial part [61]
124 Ajugamarin F4 A. decumbens whole plant [86], [88]
A. parviflora aerial part [58]
A. nipponensis aerial part [83]
125 Ajugamarin G1 A. decumbens whole plant [75], [88]
A. ciliata whole plant [87]
126 Ajugamarin H1 A. decumbens whole plant [75], [88]
A. ciliata whole plant [87]
127 Deacetylajugarin IV A. ciliata var. villosior aerial part [61]
A. remota aerial part [65]
A. ciliata whole plant [91]
128 Ajugachin A A. chamaepitys aerial part [73]
A. reptans aerial part [68]
129 Ajugachin B A. chamaepitys aerial part [73]
A. turkestanica aerial part [76]
130 Ajugacumbin A A. decumbens whole plant [59], [85], [92], [93]
A. nipponensis aerial part [83]
A. ciliata whole plant [87]
131 Ajugacumbin B A. decumbens whole plant [59], [92], [93]
A. nipponensis aerial part [83], [94]
A. macrosperma whole plant [95]
A. pantantha whole plant [95]
132 Ajugacumbin C A. decumbens whole plant [85], [92]
133 Ajugacumbin D A. decumbens whole plant [85], [92]
134 Ajugacumbin E A. decumbens whole plant [84]
135 Ajugacumbin F A. decumbens whole plant [84]
A. ciliata whole plant [87]
136 Ajugacumbin G A. decumbens whole plant [93]
137 Ajugacumbin H A. decumbens whole plant [85]
138 Ajugacumbin J A. decumbens whole plant [96]
139 Ajugavensin A A. genevensis aerial part [97]
A. reptans aerial part [70]
140 Ajugavensin B A. genevensis aerial part [97]
141 Ajugavensin C A. genevensis aerial part [97]
142 Ajugamacrin A A. macrosperma whole plant [98]
143 Ajugamacrin B A. macrosperma whole plant [98]
A. taiwanensis whole plant aerial part [89]
A. nipponensis whole plant aerial part [83]
144 Ajugamacrin C A. macrosperma whole plant [95]
A. pantantha whole plant [95]
145 Ajugamacrin D A. macrosperma whole plant [95]
A. pantantha whole plant [95]
146 Ajugamacrin E A. macrosperma whole plant [95]
A. pantantha whole plant [95]
147 Ajugapantin A A. macrosperma whole plant [95]
A. pantantha whole plant [95]
A. taiwanensis whole plant [89]
A. ciliata whole plant [87]
148 Deoxyajugarin-I A. parviflora aerial part [58]
149 Ajugarin-I chlorohydrin A. parviflora aerial part [58]
150 3β-Acetoxyclerodinin C A. parviflora aerial part [58]
151 Clerodinin A A. bracteosa whole plant [46]
152 Clerodinin C A. parviflora aerial part [58]
153 Clerodinin D A. parviflora aerial part [58]
154 15-α-Ethoxy-14-hydroajugapitin A. parviflora aerial part [58]
155 15-β-Ethoxy-14-hydroajugapitin A. parviflora aerial part [58]
156 Lupulin A A. lupulina whole plant [99]
A. bracteosa whole plant [46]
A. turkestanica

A. pseudoiva
aerial part

leaf
[76]

[78]
157 Lupulin B A. lupulina whole plant [99]
158 Lupulin C A. lupulina whole plant [99]
159 Lupulin D A. lupulina whole plant [99]
160 Lupulin E A. lupulina whole plant [4]
161 Lupulin F A. lupulina whole plant [4]
162 2β-Hydroxy-2-methylbutanoyl-3α-lupulin A. lupulina whole plant [100]
163 6-Deacetylajugarin IV A. lupulina var. major whole plant [101]
164 Ajugorientin (3β-Hydroxyajugavensin B) A. orientalis

A. reptans
aerial part

aerial part
[74]

[67], [68]
165 14,15-Dihydro-15-hydroxyajugapitin A. australis aerial part [74]
A. bracteosa whole plant [64], [79]
A. remota aerial part [65]
166 Ajugatakasin A A. decumbens leaf [75]
A. nipponensis aerial part [83]
A. ciliata whole plant [87]
167 Ajugatakasin B A. decumbens leaf [75]
A. ciliata whole plant [87]
168 14,15-Dehydroajugareptansin A. reptans aerial part [67]
169 3α-Hydroxyajugamarin F4 A. reptans aerial part [67]
170 Ajugapyrin A A. pyramidalis aerial part [102]
171 Areptin A A. reptans aerial part [68]
172 Areptin B A. reptans aerial part [68]
173 (15R)​-​14,​15-​Dihydro-​15-​hydroxyajugachin A A. laxmanii aerial part [103]
174 (15S)​-​14,​15-​Dihydro-​15-​hydroxyajugachin A A. laxmanii aerial part [103]
175 Hativene A A. pseudoiva leaf [78]
176 Hativene B A. pseudoiva leaf [78]
177 Hativene C A. pseudoiva leaf [78]
178 Hativene D A. pseudoiva leaf [104]
179 Ajugatansin A1 A. reptans aerial part [70]
180 Ajugatansin B1 A. reptans aerial part [70]
181 Ajugatansin D1 A. reptans aerial part [70]
182 Bracteonin-A A. bracteosa whole plant [79]
183 Ajugareptone A. reptans leaf [105]
184 Ajugalaevigatic acid A. chamaepitys ssp. laevigata whole plant

[51]
185 (13S)-15-Hydroxylabd-8(17)-en-19-oic acid (Imbricatoloic acid) A. chamaepitys ssp. laevigata whole plant [51]
186 Ajugalide A A. taiwanensis whole plant [89]
187 Ajugalide B A. taiwanensis whole plant [89]
A. ciliata whole plant [87]
188 Ajugalide C A. taiwanensis whole plant [89]
A. ciliata whole plant [87]
189 Ajugalide D A. taiwanensis whole plant [89]
A. ciliata whole plant [91]
190 Ajuganipponin A A. nipponensis aerial part [83]
A. ciliata whole plant [90]
191 Ajuganipponin B A. nipponensis aerial part [83]
A. ciliata whole plant [87]
A. decumbens whole plant [86]
192 14-Hydro-15-hydroxyclerodin A. remota aerial part [65]
193 14,15-Hihydroajugachin B A. turkestanica aerial part [76]
194 14-Hydro-15-methoxyajugachin B A. turkestanica aerial part [76]
195 15-epi-Lupulin A A. decumbens whole plant [106]
196 15-epi-Lupulin B A. bracteosa aerial part [64]
197 6-O-Deacetylajugamarin A. decumbens whole plant [106]
198 Ajugadecumbenins A A. decumbens whole plant [106]
199 Ajugadecumbenins B A. decumbens whole plant [106]
200 Ajubractin A A. bracteosa aerial part [64]
201 Ajubractin B A. bracteosa aerial part [64]
202 Ajubractin C A. bracteosa aerial part [64]
203 Ajubractin D A. bracteosa aerial part [64]
204 Ajubractin E A. bracteosa aerial part [64]
205 3-epi-Caryoptin A. bracteosa aerial part [64]
206 3-epi-14,15-Dihydrocaryoptin A. bracteosa aerial part [64]
207 15-Hydroxyajubractin C A. bracteosa aerial part [64]
208 14-Hydro-15-hydroxyajugachin A A. bracteosa aerial part [64]
209 Ajugaciliatin A A. ciliata whole plant [87]
210 Ajugaciliatin B A. ciliata whole plant [87]
211 Ajugaciliatin C A. ciliata whole plant [87]
212 Ajugaciliatin D A. ciliata whole plant [87]
213 Ajugaciliatin E A. ciliata whole plant [87]
214 Ajugaciliatin F A. ciliata whole plant [87]
215 Ajugaciliatin G A. ciliata whole plant [87]
216 Ajugaciliatin H A. ciliata whole plant [87]
217 Ajugaciliatin I A. ciliata whole plant [87]
218 Ajugaciliatin J A. ciliata whole plant [87]
A. decumbens whole plant [59]
219 (12S)-1β,6α,19-Triacetoxy-18-chloro-4α,12-dihydroxyneoclerod-13-en-15,16-olide A. ciliata whole plant [91]
220 (12S,2′S)-12,19-Diacetoxy-18-chloro-4α,6α-dihydroxy-1β-(2-methylbutanoyloxy)neoclerod-13-en-15,16-olide A. ciliata whole plant [91]
221 (12S)-6α,18,19-Triacetoxy-4α,12-dihydroxy-1β-tigloyloxyneoclerod-13-en-15,16-olide A. ciliata whole plant [91]
222 (12S)-6α-Acetoxy-4α,18-epoxy-12-hydroxy-19-tigloyloxyneoclerod-13-en-15,16-olide A. ciliata whole plant [90]
223 6α,18-Diacetoxy-4α-hydroxy-19-tigloyloxyneoclerod-13-en-15,16-olide A. ciliata whole plant [90]
224 Ajugamarin A2 chlorohydrin A. ciliata whole plant [87]
225 6α,19-Diacetoxy-4α-hydroxy-1β-tigloyloxyneoclerod-12-en-15-oic acid methyl ester-16-aldehyde A. decumbens whole plant [59]
226 (12S)-18,19-Diacetoxy-4α,6α,12-trihydroxy-1β-tigloyloxyneoclerod-13-en-15,16-olide A. decumbens whole plant [59]
227 4α,6α-Dihydroxy-18-(4′-methoxy-4′-oxobutyryloxy)-19-tigloyloxyneoclerod-13-en-15,16-olide A. decumbens whole plant [59]
228 (12S)-1α,19-Epoxy-6α,18-diacetoxy-4α,12-dihydroxyneoclerod-13-en-15,16-olide A. decumbens whole plant [86]
229 (12S)-6α,19-Diacetoxy-18-chloro-4α-hydroxy-12-tigloyloxyneoclerod-13-en-15,16-olide A. decumbens whole plant [86]
230 (12S,2′′S)-6α,19-Diacetoxy-18-chloro-4α-hydroxy-12-(2-methylbutanoyloxy)neoclerod-13-en-15,16-olide A. decumbens whole plant [86]
231 Ajugacumbin A chlorohydrin A. ciliata whole plant [87]
A. decumbens whole plant [59]
232 Ajuforrestin A A. forrestii whole plant [107]
A. decumbens aerial part [7]
233 Ajuforrestin B A. forrestii whole plant [107]
A. decumbens aerial part [7]
234 Ajugaside A A. decumbens whole plant [108]
235 Ajudecumin A A. decumbens aerial part [7]
236 Ajudecumin B A. decumbens aerial part [7]
237 Ajudecumin C A. decumbens aerial part [7]
238 Ajudecumin D A. decumbens aerial part [7]
239 Carnosol A. forrestii whole plant [109]
240 Epiisorosmanol A. forrestii whole plant [109]
241 2,11,12-Trihydroxy-7,20-epoxy-8,11,13-abietatriene A. forrestii whole plant [109]
242 Epirosmanol A. forrestii whole plant [109]
243 7-Methoxyrosmanol A. forrestii whole plant [109]
244 7-Ethoxyrosmanol A. forrestii whole plant [109]
245 2α,3β,11,12-Tetrahydroxy-7β,20-epoxy-8,11,13-abietatriene A. forrestii whole plant [109]
Figure 5 Diterpenoids.

Figure 5

Diterpenoids.

Neoclerodanes

Most of the neoclerodane diterpenoids produced by species of the genus Ajuga contain a substituted decalin with a 4α,18-oxirane ring and two oxygenated substituents bound to C(6) and C(19) [110]. The side chain features several moieties with the most common being: (i) a butenolide function (α-substituted α,β-unsaturated γ-lactone, or 13-en-15,16-olide) as in 89–93 isolated from A. remota [2], [60], [62]; (ii) a tetrahydrofurofuran as in 94 reported as a constituent of A. remota [63]; and (iii) a hexahydrofurofuran as in 95 reported as a component of Ajuga parviflora [58]. In 1983, three new bitter principles, 106–108, were isolated from the leaves of A. nipponensis. The β-hydrin structure of 108 was confirmed by treatment of 106 with methanolic HCl [81], [82]. In addition, by reinvestigation of the aerial parts of A. nipponensis, four new bitter neoclerodanes 112, 113, 116, 117 and a known diterpenoid 89 were isolated [57]. The configuration of methoxy group at C(15) (R5) of lupulin A (156) [99] was revised to be α by Huang and co-workers [106]. Consequently, hativene D (178) [104] is not 15-epi-lupulin (195) but lupulin (156). The structure of 15-epi-lupulin B (196) [64] with a 2β-OH group coincides with lupulin A 156.

Abietanes

A new abietane diglucopyranoside 234 was isolated from the whole plants of A. decumbens [108]. In the course of the search for bioactive metabolites with anticancer effects, Wang et al. isolated four new rearranged abietane hydroquinones 235–238, together with two known abietanes 232 and 233 from the aerial parts of A. decumbens collected in China [7].

Sesquiterpenoids (Table 6, Figure 6)

Only a few other sesquiterpenoids, bisabolene, eudesmanolides and seco-sesquiterpenoids, were reported. Compound 246, a bisabolene sesquiterpenoid, was isolated from the aerial parts of A. decumbens [7]. Research on Ajuga forrestii resulted in the isolation of four eudesmane sesquiterpene lactones 247–250. Among them, compounds 247–249 are new. Compound 249 exhibits weak cytotoxic activity against HepG2 and MCF-7 human cell lines [109]. Four megastigmane derivatives 251–254 and 257 were isolated in 2012 [7], [112]. A new ionone glycoside 255 was also isolated from this plant. This is the first report of the occurrence of ionone glycosides in Ajuga species [111].

Table 6

Sesquiterpenoids.

No. Name Source Part Ref.
246 Glecholone A. decumbens aerial part [7]
247 3α-Acetoxy-1α,8β-dihydroxyeudesm-7(11)-en-8,12-olide A. forrestii whole plant [109]
248 3α-Acetoxy-1α-hydroxyeudesm-8,7(11)-dien-8,12-olide A. forrestii whole plant [109]
249 1α-Acetoxy-8α-oxyethyl-2-oxoeudesman-3,7(11)-dien-8,12-olide A. forrestii whole plant [109]
250 1α-Acetoxy-8α-hydroxy-2-oxoeudesman-3,7(11)-dien-8,12-olide A. forrestii whole plant [109]
251 (6R,7E,9R)-9-Hydroxy-4,7-megastigmadien-3-one A. decumbens aerial part [7]
252 (3S,5R,6S,7E)-5,6-Epoxy-3-hydroxy-7-megastigmen-9-one A. decumbens aerial part [7]
253 (6E,9S)-9-Hydroxy-4,6-megastigmadien-3-one A. decumbens aerial part [7]
254 6-Hydroxy-4,7-megastigmadiene-3,9-dione A. decumbens aerial part [7]
255 4β-Hydroxy-7,8-dihydro-3-oxo-β-ionol 9-O-β-D-glucopyranoside A. salicifolia aerial part [111]
256 Corchoionoside C A. salicifolia aerial part [111]
257 Loliolide A. decumbens whole plant [112]
Figure 6 Sesquiterpenoids.

Figure 6

Sesquiterpenoids.

Monoterpenoids (Table 7, Figure 7)

Major monoquiterpenoids isolated from the genus Ajuga belong to iridoids. In 1974, Guiso and co-workers isolated three iridoid glucopyranosides 258–260 from A. reptans. Compound 259 is an 8-O-acetyl derivative of 260 and a 6-epimer of 8-O-acetylmioporoside 271 [113], [117]. Four new iridoid glucopyranoside cis- and trans-p-coumaroyl esters 263–266 were isolated from methanol extract of the dried plant of A. decumbens, together with the known compounds 258 and 262 [116]. Compound 270, isolated from the leaves of Ajuga pseudoiva, possesses an unusual 13-membered macrocyclic structure [121].

Table 7

Iridoids.

No. Name Source Part Ref.
258 Reposide A. reptans whole plant [113], [114], [115]
A. decumbens whole plant [116]
259 Ajugoside A. reptans whole plant [117]
260 Ajugol A. reptans whole plant [117]
261 Jaranidoside A. spectabilis whole plant [118]
262 8-O-Acetylharpagide A. multiflora whole plant [119]
A. remota aerial part [6]
A. decumbens whole plant [116]
A. iva aerial part [120]
A. reptans whole plant [114], [115]
263 Decumbeside A A. decumbens whole plant [116]
264 Decumbeside B A. decumbens whole plant [116]
265 Decumbeside C A. decumbens whole plant [116]
266 Decumbeside D A. decumbens whole plant [116]
267 Harpagide A. iva aerial part [120]
A. reptans whole plant [114], [115]
268 6-Deoxyharpagide A. iva aerial part [120]
269 Ajureptoside A. reptans whole plant [114]
270 7-O-6′-O-Malonylcachinesidic acid A. pseudoiva leaf [121]
271 8-O-Acetylmioporoside A. salicifolia aerial part [111]
272 Galiridoside A. taiwanensis whole plant [19]
273 Teuhircoside A. taiwanensis whole plant [19]
274 6-Keto-8-acetylharpagide A. remota aerial part [122]
275 6,7-Dehydro-8-acetylharpagide A. remota aerial part [122]
276 7,8-Dehydroharpagide A. remota aerial part [122]
277 8-Acetylharpagide 6-O-β-glucopyranoside A. remota aerial part [122]
278 Harpagide 6-O-β-glucopyranoside A. remota aerial part [122]
279 2′,3′-Diacetylharpagide A. remota underground part [123]
280 6′-O-Rhamnosylharpagide A. remota underground part [123]
281 6′-O-Galloyl-7,8-dehydroharpagide A. remota underground part [123]
282 6-O-Xylosylharpagoside-B A. remota underground part [123]
283 Ajureptaside A A. reptans whole plant [115]
284 Ajureptaside B A. reptans whole plant [115]
285 Ajureptaside C A. reptans whole plant [115]
286 Ajureptaside D A. reptans whole plant [115]
287 6-epi-8-O-Acetylharpagide A. reptans whole plant [115]
Figure 7 Iridoids.

Figure 7

Iridoids.

Flavonoids (Table 8, Figure 8)

Flavonoids 288–305 including flavones and flavonols isolated from the genus Ajuga are outlined in Table 8.

Table 8

Flavonoids.

No. Name Source Part Ref.
288 Luteolin A. chia aerial part [124]
A. lupulin whole plant [101], [125]
289 Luteolin 7-O-glucopyranoside A. chia aerial part [124]
A. lupulina whole plant [101], [125]
290 Apigenin A. chia aerial part [124]
A. multiflora aerial part [126]
A. forrestii whole plant [107]
291 Naringin A. iva aerial part [15]
292 Apigenin ​7-​O-​neohesperidoside A. iva aerial part [15]
293 Chrysoriol A. lupulina whole plant [125]
294 Diosmetin A. lupulina whole plant [125]
295 Kaempferide A. lupulina whole plant [125]
296 Quercetin A. lupulina whole plant [125]
297 Acacetin A. forrestii whole plant [107]
298 Gnetifolin B A. forrestii whole plant [107]
299 Apigenin 7-glucuronide A. multiflora aerial part [18]
300 Kaempferol A. taiwanensis whole plant [19]
301 Myricetin 3-O-rutinoside 4′-O-rutinoside A. remota aerial part [122]
302 Myricetin 3-O-rutinoside 3′-O-rutinoside A. remota aerial part [122]
303 Isorhamnetin 3-O-rutinoside 7-O-rutinoside 4′-O-β-glucopyranoside A. remota aerial part [122]
304 3,4′-Dihydroxy-3,6,7-trimethoxyflavone A. bracteosa whole plant [127]
305 7-Hydroxy-3,6,3′,4′-tetramethoxyflavone A. bracteosa whole plant [127]
Figure 8 Flavonoids.

Figure 8

Flavonoids.

Polyketides and alkaloids (Table 9, Figure 9)

From the leaves of A. iva, three new homologous 1,3-diglycerides 331–333 and compound 339 were obtained. In 1986, Takasaki and co-workers isolated three phenethyl alcohol glycosides 323–325, including a new derivative 323 [108]. A phenylalanine derivative 346 was isolated from this plant recently [96]. In addition, Yu and co-workers isolated a phthalic ester 321 from the aerial parts of A. multiflora [18].

Table 9

Polyketides and alkaloids.

No. Name Source Part Ref.
306 Ethyl (1-acetoxy-4-oxo-2,5-cyclohexadien-1-yl)acetate A. parviflora whole plant [128]
307 Methyl (1-acetoxy-4-oxo-2,5-cyclohexadien-1-yl)acetate A. parviflora whole plant [128]
308 Ethyl (1-hydroxy-4-oxo-2,5-cyclohexadien-1-yl)acetate A. parviflora whole plant [128]
309 Methyl (1-hydroxy-4-oxo-2,5-cyclohexadien-1-yl)acetate A. parviflora whole plant [128]
310 (1-Hydroxy-4-oxo-2,5-cyclohexadien-1-yl)acetic acid A. parviflora whole plant [129]
311 2-Hydroxy-4β-methyl-4α-(β-D-glucopyranoside)-2,5-cyclohexadien-1-one A. parviflora whole plant [129]
312 Methyl 2-(2,2-dimethyl-6-oxo-7-dihydro-1,3-benzodioxol-3(6H)-yl)acetate A. parviflora whole plant [129]
313 6,7-Dihydroxycoumarin (Esculetin) A. decumbens whole plant [52]
314 Coumarin A. laxmanii aerial part [103]
315 Vanillic acid A. decumbens whole plant [112]
A. taiwanensis whole plant [19]
316 Melilotic acid methyl ester A. laxmanii aerial part [103]
317 Methyl caffeate A. decumbens whole plant [112]
318 Methyl (E)-4-acetoxy-3-methoxycinnamate A. pseudoiva leaf [38]
319 Methyl (E)-4-acetoxycinnamate A. pseudoiva leaf [38]
320 Ajuganane A. bracteosa whole plant [127]
321 Bis(2-ethylhexyl) phthalate A. multiflora aerial part [18]
322 Bis(2S-methylheptyl) phthalate A. bracteosa whole plant [130]
323 Galactosylmartynoside A. decumbens whole plant [108]
324 Martynoside A. decumbens whole plant [108]
325 Darendoside B A. decumbens whole plant [108]
326 Lavandulifolioside A. salicifolia aerial part [111]
327 Leonoside A A. salicifolia aerial part [111]
328 Leonoside B A. salicifolia aerial part [111]
329 1-Ethenylhexyl 6-O-β-L-arabinopyranosyl-2-O-β-D–glucopyranosyl-β-D-glucopyranoside A. decumbens whole plant [52]
330 Butyl β-D-fructopyranoside A. decumbens whole plant [52]
331 Ivade A A. iva leaf [131]
A. pseudoiva leaf [48]
332 Ivade B A. iva leaf [131]
A. pseudoiva leaf [48]
333 Ivade C A. iva leaf [131]
A. pseudoiva leaf [48]
334 Hizivaide A A. pseudoiva leaf [132]
335 Hizivaide B A. pseudoiva leaf [132]
336 Hizivaide C A. pseudoiva leaf [132]
337 Hizivaide D A. pseudoiva leaf [132]
338 Hizivaide E A. pseudoiva leaf [132]
339 Methyl 3-hydroxyhexadecanoate A. iva leaf [133]
340 (10E,15Z)-9,12,13-Trihydroxyoctadeca-10,15-dienoic acid A. decumbens whole plant [112]
341 Heptacos-3-en-25-one A. bracteosa aerial part [134]
342 Bractic acid A. bracteosa whole plant [10]
343 Ligularinine A. parviflora whole plant [44]
344 Senecionine A. parviflora whole plant [45]
345 Integerrimine A. parviflora whole plant [45]
346 Aurantiamide acetate A. decumbens whole plant [96]
347 Pheophytin-a A. taiwanensis whole plant [19]
348 Pheophytin-b A. taiwanensis whole plant [19]
349 132-Hydroxy(132-S)pheophytin-a A. taiwanensis whole plant [19]
351 Nicotinic acid A. taiwanensis whole plant [19]
352 Bractin A A. bracteosa whole plant [10]
353 Bractin B A. bracteosa whole plant [10]

During the search for bioactive metabolites from A. pseudoiva leaves, Ben and co-workers isolated five novel monoglycerides 334–338, two novel cinnamic acids 318, 319 and one new steroid 63, along with five known compounds 61, 62, 331–333. Three compounds 331–333 show significant antifeedant activity, which might be associated with the presence of two β-hydroxyalkanoic moieties in each compound [38], [48], [50], [132]. A phytochemical investigation on A. parviflora resulted in the isolation of quinols 306–312 and pyrrolizidine alkaloids 343–345. Derivatives 306–308 are new compounds. Compound 309, isolated previously from the leaves and branches of Jacaranda species, display cytotoxic and antitumor activities. Three pyrrolizidine alkaloids 343–345 were reported for the first time from this plant [44], [45], [128], [129].

The plant of Ajuga bracteosa afforded several new compounds including unsaturated ketone 341, phthalic ester 322, phenolic compound 320, two sphingolipids 352, 353 and a long-chain polyhydroxy acid 342 [10], [130], [134].

Figure 9 Polyketides and alkaloids.

Figure 9

Polyketides and alkaloids.

Biological activity

Antifeedant and larvicidal activity

A neoclerodane 103 was isolated from the leaves of A. decumbens as a feeding stimulant for Athalia rosae ruficornis [75]. Three new neoclerodanes 164, 168, 169 were isolated from the aerial parts of A. reptans cv. catlins giant. Insect antifeedant testing revealed that 168 has significant activity against sixth stadium larvae of Spodoptera littoralis [67]. A series of active clerodanes 104, 156, 175–177 were isolated from the acetone extract of A. pseudoiva leaves by bioassay-guided chromatography. The behavioral responses of Spodoptera littoralis larvae to all clerodanes showed strong antifeedant activity at 100 to 1 mg/L. In addition, this study also indicated that a methoxy group at C(15), either in the α- or β-position, might decrease antifeedant activity [9]. Manguro and co-workers tested larvicidal activity of the extracts of A. remota using second instar Aedes aegypti larvae [123]. The ethyl acetate extract is toxic with LC50 value of 5.30 μg/L, while the methanol extract displays weak toxicity with an LC50 of 65.94 μg/L. Compound 81, obtained from the ethyl acetate extract, is the active component with an LC50 value of 4.40 μg/L.

Antimicrobial activity

Compounds 156–161 are six new neoclerodanes isolated from Ajuga lupulina. The diterpenoids 156 and 160 show strong activity against Pseudomonas aeruginosa and Escherichia coli (inhibitory zones are 3–5 mm and 3.5–4.5 mm, respectively, at a concentration of 0.02 mg/mL). In addition, 156 displays weak activity against Staphylococcus aureus (1.5 mm). The antibacterial activity of 161 against P. aeruginosa (2.1 mm) and E. coli (2.0 mm) is poor compared to 156 and 160. Compound 157 exhibits weak antibacterial activity against S. aureus and E. coli (1.2 mm) [4], [99]. In 2001, Kariba tested the extracts of A. remota for in vitro antifungal activity. The petroleum ether and methanol extracts exhibit antifungal activity against the dermatophytic fungi Trichophyton mentagrophytes and Microsporum gypseum [5]. Ergosterol 5,8-endoperoxide 81, isolated from the methanol extract of A. remota, shows activity against Mycobacterium tuberculosis [55].

Antimalarial activity

Ajuga remota is commonly used as medicinal herb for malaria treatment in Kenya. Three isolates, 81, 89 and 262, were tested for their in vitro antiplasmodial activity. Compound 89 is moderately active against a chloroquine-sensitive (FCA 20/GHA) strain of Plasmodium falciparum, with an IC50 of 23.0 μm, compared to a 0.041 μm IC50 for chloroquine. Compared to 89, compound 262 is approximately 3 times as potent. Compound 262 is also equally potent towards chloroquine-sensitive (FCA 20/GHA) and chloroquine-resistant (W2) strains [6]. An excellent review article summarizes antimalarial activity of compounds contained in A. remota and A. bracteosa [135].

Anti-inflammatory activity

Gautam et al. tested a 70% ethanol extract of A. bracteosa whole plants in a mice acute inflammation model based on topical application of TPA. The result showed that the extract exhibits a remarkable and dose-dependent anti-inflammatory activity at 0.5 and 1.0 mg/ear. In addition, it showed a significant in vitro COX-1 and COX-2 inhibitory activity at 25 and 50 μg/mL. Among the isolates from the bioactive extract, compound 156 exhibited the highest inhibition of COX-1, and compound 268 displayed the highest inhibition of COX-2 [136]. The compounds 342, 352, 353 exhibited remarkable inhibition of lipoxygenase. Compound 342 was more active than baicalein (IC50=22.4 μm) with an IC50 of 10.0 μm [10].

Hypoglycemic activity

Ajuga iva has been used as traditional medicine to control diabetes mellitus for many centuries. In 2002, a study to examine the hypoglycemic effect of A. iva was carried out, and the results demonstrated that A. iva aqueous extract exhibits strong hypoglycemic activity. Lyophilized aqueous extract of A. iva whole plant was found to decrease plasma glucopyranose levels of streptozotocin-induced diabetic rats from 337 to 102.2 mg/dL after 6 h of oral administration. Furthermore, repeated oral administration significantly reduced plasma glucopyranose levels after 1 week of treatment (112 mg/dL at 1 week vs. 337 mg/dL at the baseline values) [137].

Cytotoxic activity

Compounds 70–75 are five new sterol glycosides isolated from a methanol extract of the aerial parts of A. salicifolia. Their cytotoxicity against HeLa cells (KB), human T cell leukemia (Jurkat), and peripheral mononuclear blood cells (PMBC) have been evaluated. Compounds 70–74 significantly inhibit the viability and growth of Jurkat T cells at concentrations below 10 μm. Compound 73 is the most active substance with an IC50 values of 3 μm, followed by 70 (IC50=6 μm). An additional glucopyranose substituent leads to weaker cytotoxicity against Jurkat T cells, as observed for 71 (IC50=10 μm) and 74 (IC50=8 μm). Compound 70 induces cell-cell contacts in a Jurkat T cell population, and remarkably up-regulated mRNA levels of the cell-cycle regulator cyclin D1, which might be an indication for cell differentiation [53]. In 2003, Akbay and co-workers investigated the cytotoxicity of sterols obtained from A. salicifolia against KB (HeLa) and Jurkat T cancer cells. This study demonstrated that compound 72 is active against KB cells with an IC50 of 1 μg/mL, while the corresponding 3-O-β-glucopyranoside, compound 76, is less potent (IC50=13 μg/mL) [54]. Four new A. decumbens abietane diterpenoids, 235–238, were evaluated for in vitro inhibition of cell proliferation. The diterpenoids 235 and 237 exhibit moderate cytotoxic activities against MCF-7 cells (human breast cancer), with IC50 values of 19.4 and 12.5 μm, respectively [7].

Cholinesterase inhibitory activity

Compounds 95, 104, 151, 156, 342, 352 and 353 were obtained from A. bracteosa, and their enzyme-inhibitory potential was evaluated. The diterpenoids 95, 104, 151 and 156 display inhibitory activity against cholinesterase (AChE and BChE) with IC50 values in the range of 14.0–35.2 μm for AChE and 10.0–19.0 μm for BChE, respectively. Compound 104 is the most active against cholinesterase while 156 is comparatively less active, indicating that the presence of a MeO group at C(15) increases the cholinesterase inhibitory activity [10].

Antioxidative activity

Bouderbala and co-workers studied the effect of A. iva aqueous extract on lipid peroxidation and antioxidant enzyme activity in hypercholesterolemic rats. The results showed that A. iva extract is more effective at improving RBC antioxidant capacity relative to that of tissues. In addition, A. iva aqueous extract can reduce oxidative stress, which may prevent lipid peroxidation in hypercholesterolemic models by increasing antioxidant enzyme activity [138].

Vasorelaxant activity

El-Hilaly and co-workers investigated vascular activity of A. iva aqueous extract in normotensive Wistar rats. The aqueous extract displayed NO-mediated and NO-independent vasorelaxing properties in vitro. The A. iva extract contains more than one active compound. One of these compounds is responsible for inhibition of noradrenaline evoked contraction. Another compound was identified in vitro as a transient NO-dependent relaxation [8].

Conclusions

The plants of the genus Ajuga are widely distributed globally and many of these plants are used as traditional herbal medicines. The compounds isolated from this genus exert a broad spectrum of biological and pharmacological activities, however, our review indicates that phytochemical investigation has mainly focused on a few species. Further studies on the remaining species, their constituents and biological activities, should be carried out.

Funding source: National Natural Science Foundation of China

Award Identifier / Grant number: 81302664

Award Identifier / Grant number: 81241101

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Received: 2017-3-24
Accepted: 2017-6-15
Published Online: 2017-7-22
Published in Print: 2017-8-28

©2017 Walter de Gruyter GmbH, Berlin/Boston

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