In Africa, much like elsewhere in the whole world, plants have always been an important source of natural products with very high therapeutic values. Many people are still interested in using natural products from plants for curative and preventive medicine. Thus, it has been estimated that over 60% of the world population and 80% of the population of developing countries still directly rely on medicinal plants, for their primary health care needs . Hostettmann et al.  stated that in some African countries, up to 90% of the population still depended exclusively on medicinal plants as a source of medicines. Nowadays, people are still very interested in medicinal plants. Thus, with this growing interest in the field of medicinal plants, there is a great need to produce databases that would contain as much information as possible about the secondary metabolites produced by plants and their importance in today’s world. About 15% of the known angiosperm species in tropical regions have been examined for their pharmacological properties . Therefore, there are most definitely a large number of plant-derived medicines and other useful compounds that have yet to be discovered and characterized around the world.
Cameroon has a very rich and diverse flora estimated in 2003 at 8,620 known plants species , that a large majority of population are using some of them as medicines for their primary healthcare. However, in the Cameroonian pharmacopoeia, there is still a serious lack of information on the uses and the phytochemical content of a large number of plants and spices traditionally employed in the treatment of several ailments. Gardenia aqualla Stapf & Hutch (Rubiaceae) is among those medicinal plants extensively used in Cameroon and not well documented.
Known as “Dingale” in Fufulde in the Adamawa Region of Cameroon, Gardenia aqualla is a bushy shrub or a small tree that grows up to 3 m high and belongs to the Sudanese to Sudano-Guinean savannahs on shady lowlands and alluvial terraces . It is widely distributed from Senegal to Cameroon and as far as Sudan, scattered, locally common. Medicinally, the plant is used in the treatment of several ailments such as leprosy, oral and ear infections , dysmenorrhea , jaundice, ulcers , diabete , syphilis , cancer .
As the plant is being used extensively in our country as an herbal medicine, it is necessary to have knowledge of the constituents of the plant of our native species. Previous phytochemical investigation on this species revealed the presence of steroids, triterpenes and flavonoids in the petroleum ether extract of the stem barks while the methanolic extract was found to contain anthraquinones, carbohydrates, cardiac glycosides, flavonoids, saponins, steroids, tannins and triterpenes . To the best of our knowledge, currently no compound has been isolated from this plant species. The present study aims therefore to investigate chemical constituents of this herbal medicine.
2 Experimental Procedures
2.1 Plant material
The Stem barks of G. aqualla Stapf & Hutch were collected at Dang in the District of Ngaoundere III, Region of Adamawa Cameroon. A voucher is deposited at National Herbarium of Cameroon in Yaounde under number 36894/HNC.
2.2 Extraction and isolation
The ground dried stem barks (1.00 kg) were consecutively extracted with Hexane, EtOAc and MeOH to give 6.74 g, 9.42 g and 83.83 g of extracts respectively. A portion (50.0 g) of the MeOH extract was fractionated by silica gel column chromatography using a gradient elution with successively Hexane-EtOAc (1:0→0:1) and EtOAc-MeOH (1:0→0:1). 510 sub-fractions of 300 mL were collected and according to their chromatographic profiles on TLC, they were grouped into six fractions G1-G6. From the main column seven compounds were obtained, compound 1 at Hexane-EtOAc (9:1) from the assembly of sub-fractions 17-53, compound 2 at Hexane-EtOAc (1:1) from the assembly of sub-fractions 242-253, compound 5 at Hexane-EtOAc (1:9) from the assembly of sub-fractions 321-366 and compound 6 at EtOAc-MeOH (9:1) from the assembly of sub-fractions 400-402. Fraction G3 (1.96 g) was further purified on CC of silica gel using a gradient polarity of hexane-EtOAc (1:0→6:4) leading to compound 3 from the sub-fractions 17-18, compound 4 from the sub-fractions 21-22, and from the assembly of sub-fractions 25-28 compounds 7, 8 and 9 were obtained as a mixture. All these last five compounds were obtained at the same polarity (Hexane-EtOAc (9:1)). Nonacosane (1): white solid, m.p. 50–51°C. TOF-MS-ESI+: [M+H]+ at m/z = 409.3, [M+K]+ at m/z = 447.3, and [2M+K+H]+ at m/z = 856.5 for C29H60. 1H NMR (CDCl3): δ 0.91 (6H, t, J = 7.0 Hz, 3H-1, 3H-29), 1.59 (4H, m, 2H-2, 2H-28) and 1.20-1.39 [(CH2)n, brs]. 13C NMR (CDCl3): δ 14.1 (C-1, C-29), 22.7 (C-2, C-28), 31.9 (C-3, C-27), and 29.4–29.7 (C-4–C-26) .
Heptatriacontanol (2): white solid, m.p. 88–89°C. TOF-MS-ESI+: [M+H]+ at m/z = 537.3, for C37H76O. 1H NMR (CDCl3): δ 3.65 (2H, m, 2H-1), 1.60 (2H, m, 2H-2), 1.20-1.39 [(CH2)n, brs] and 0.89 (3H, t, J = 7.5 Hz, 3H-37). 13C NMR (CDCl3): δ 63.1 (C-1), 32.8 (C-2), 25.7 (C-3), 29.4-29.7 (C-4-C-34), 31.9 (C-35), 22.7 (C-36) and 14.1 (C-37). 
Docosanol (3): white solid, m.p. 58–59°C. TOF-MS-ESI+: [M+6NH4++6H]+ at m/z = 440.2 and [M+4NH4++3H]+ at m/z = 401.4, for C22H46O. 1H NMR (CDCl3): δ 3.67 (2H, t, J = 6.6 Hz, 2H-1), 1.59 (2H, m, 2H-2), 1.29 [(CH2)n, brs] and 0.91 (3H, t, J = 7.0 Hz, 3H-22). 13C NMR (CDCl3): δ 63.1 (C-1), 32.8 (C-2), 25.7 (C-3), 29.4–29.7 (C-4–C-19), 31.9 (C-20), 22.7 (C-21) and 14.1 (C-22). 
Heptadecyl heptacosanoate (4): white solid, m.p. 65–66°C. TOF-MS-ESI+: [M+2NH4++H]+ m/z = 685.3 for C44H88O2. 1H NMR (CDCl3): δ 0.81 (6H, t, J = 7.0 Hz, 3H-27, 3H-17′), 1.20-1.33 [(CH2)n, brs], 1.54 (4H, m, 2H-3, 2H-2′), 2.22 (2H, t, J = 7.5 Hz, 2H-2), 4.00 (2H, t, J = 6.7 Hz, 2H-1′). 13C NMR (CDCl3): δ 174.0 (C-1), 64.4 (C-1′), 34.4 (C-2), 31.9 (C-25 and C-15′), 29.2-29.7 (C-4–C-24 and C-4′–C14′), 28.7 (C-2′), 26.0 (C-3′), 25.1 (C-3), 22.7 (C-26 and C-16′) and 14.1 (C-27 and C-17′).
D-mannitol (5): white solid, m.p. 168–169°C. TOF-MS-ESI+: [2M+Na]+ at m/z = 387.2 for C6H14O6. 1H NMR (DMSO-d6): δ 4.41 (2H, d, J = 5.5 Hz, HO-2 and 5), 4.33 (2H, t, J = 5.7 Hz, HO-1 and 6), 4.13 (2H, d, J = 7.1 Hz, HO-3 and 4), 3.62 (2H, ddd, J = 10.8, 5.7, 3.5 Hz, H-1a and 6a), 3.56 (2H, t, J = 7.5 Hz, H-3 and 4), 3.47 (2H, m, H-2 and 5) and 3.39 (2H, m, H-1b and 6b). 13C NMR (DMSO-d6): δ 63.8 (C-1 and 6), 71.3 (C-2 and 5) and 69.7 (C-3 and 4). 
D-mannitol acetate (6): white solid, m.p. 123–124°C. TOF-MS-ESI+: [M+Na]+ at m/z = 247.1 and [M+Na]+ at m/z = 471.1 for C8H16O7 1H NMR (DMSO-d6): δ 4.75 (1H, d, J = 5.6 Hz, HO-2), 4.41 (1H, d, J = 5.5 Hz, HO-5), 4.33 (1H, t, J = 5.7 Hz, HO-6), 4.28 (2H, ov, H-1a and HO-3), 4.14 (2H, d, J = 7.1 Hz, HO-4), 3.96 (1H, m, H-1b), 3.68 (1H, m, H-2), 3.62 (1H, m, H-6a), 3.54 (2H, m, H-3 and 4), 3.47 (1H, m, H-5) and 3.40 (1H, m, H-6b), 2.03 (3H, s, OCOCH3). 13C NMR (DMSO-d6): δ 20.8 (-OCOCH3), 63.8 (C-6), 67.0 (C-1), 68.2 (C-2), 69.3 (C-3), 69.4 (C-4), 71.2 (C-5) and 170.5 (-OCOCH3).
β-sitosterol (7): white solid. 1H-NMR (CDCl3), δ: 5.35 (1H, d, J = 5.1 Hz, H-6), 3.53 (1H, ddd, J = 15.9, 11.0, 4.6 Hz, H-3), 1.04 (3H, s, H-19), 1.01 (3H, d, J = 7.0 Hz, H3-27), 0.95 (3H, d, J = 6.6 Hz, H3-26), 0.88 (3H, d, J = 1.8 Hz, H3-21), 0.85 (3H, ov, H3-29) and 0.71 (3H, s, H3-18). 13C-NMR (CDCl3 ): δ 37.3 (CH2, C-1), 31.9 (CH2, C-2), 71.8 (CH, C-3), 42.4 (CH2, C-4), 140.8 (C-5), 121.7 (CH, C-6), 31.7 (CH2, C-7), 31.9 (CH, C-8), 50.2 (CH, C-9), 36.6 (C, C-10), 21.1 (CH2, C-11), 39.8 (CH2, C-12), 42.3 (CH, C-13), 56.8 (CH, C-14), 24.3 (CH2, C-15), 28.2 (CH2, C-16), 56.1 (CH, C-17), 11.9 (CH3, C-18), 19.0 (CH3, C-19), 36.2 (CH2, C-20), 18.8 (CH3, C-21), 34.0 (CH2, C-22), 26.3 (CH2, C-23), 45.9 (CH, C-24), 29.3 (CH, C-25), 19.4 (CH3, C-26), 19.8 (CH3, C-27), 23.1 (CH2, C-28), 12.0 (CH3, C-29). 
Stigmasterol (8): white solid. 1H NMR (CDCl3), δ: 5.38 (1H, m, H-6), 5.14 (1H, ov, H-22), 5.05 (1H, dd, J = 15.2, 8.7 Hz, H-23), 3.56 (1H, ddd, J = 15.8, 11.0, 4.5 Hz, H-3), 1.04 (3H, s, H-19), 1.01 (3H, d, J = 7.0 Hz, H3-27), 0.95 (3H, d, J = 6.6 Hz, H3-26), 0.88 (3H, d, J = 1.8 Hz, H3-21), 0.85 (3H, ov, H3-29) and 0.71 (3H, s, H3-18). 13C NMR (CDCl3) δ: 37.2 (CH2, C-1), 31.9 (CH2, C-2), 71.8 (CH, C-3), 42.3 (CH2, C-4), 140.8 (C, C-5), 121.7 (CH, C-6), 31.7 (CH2, C-7), 31.9 (CH, C-8), 50.2 (CH, C-9), 36.5 (C, C-10), 21.1 (CH2, C-11), 39.8 (CH2, C-12), 42.3 (C, C-13), 56.8 (CH, C-14), 24.3 (CH2,C-15), 28.2 (CH2, C-16), 56.1 (CH, C-17), 12.1 (CH3, C-18), 19.0 (CH3, C-19), 40.5 (CH2, C-20), 18.8 (CH3, C-21), 138.4 (CH, C-22), 129.3 (CH, C-23), 51.2 (CH, C-24), 45.9 (CH, C-25), 19.4 (CH3, C-26), 19.8 (CH3,C-27), 24.3 (CH2, C-28), 12.3 (CH3, C-29). 
Fucosterol (9): white solid. 1H NMR (CDCl3), δ: 5.38 (1H, m, H-6), 5.17 (1H, ov, H-28), 3.56 (1H, ddd, J = 15.8, 11.0, 4.5 Hz, H-3), 1.57 (3H, ov, H-29), 1.04 (3H, s, H-19), 1.01 (3H, d, J = 7.0 Hz, H3-27), 0.95 (3H, d, J = 6.6 Hz, H3-26), 0.88 (3H, d, J = 1.8 Hz, H3-21) and 0.71 (3H, s, H3-18). 13C NMR (CDCl3) δ: 37.2 (CH2, C-1), 31.9 (CH2, C-2), 71.8 (CH, C-3), 42.3 (CH2, C-4), 140.8 (C, C-5), 121.7 (CH, C-6), 31.7 (CH2, C-7), 31.9 (CH, C-8), 50.2 (CH, C-9), 36.5 (C, C-10), 21.1 (CH2, C-11), 39.8 (CH2, C-12), 42.3 (C, C-13), 56.8 (CH, C-14), 24.3 (CH2,C-15), 28.2 (CH2, C-16), 56.1 (CH, C-17), 11.8 (CH3, C-18), 19.3 (CH3, C-19), 36.5 (CH2, C-20), 18.8 (CH3, C-21), 36.1 (CH, C-22), 26.1 (CH, C-23), 145.9 (CH, C-24), 34.0 (CH, C-25), 21.1 (CH3, C-26), 21.1 (CH3,C-27), 116.4 (CH2, C-28), 12.8 (CH3, C-29). 
2.3 Antimicrobial assays
Antibacterial and anticandidal activities of isolated compounds were performed against four bacterial strains (Salmonella Typhimurium ATCC6539, Pseudomonas aeruginosa ATCC9721, Escherichia coli, and S. Typhi isolate) and four strains of yeast (Candida albicans ATCC9002, Candida parapsilosis ATCC22019, Candida krusei and Candida albicans isolate). Minimum inhibitory concentrations (MICs), minimum bactericidal concentrations (MBCs) and minimum fungicidal concentrations (MFCs) were determined by the broth microdilution method as previously described by Nyemb et al.  and Dzoyem et al.  respectively for antibacterial and antifungal activities. Ciprofloxacin was used as standard drug for antibacterial assay, while ketoconazole was used as positive control for the antifungal assay. All the experiments were carried out in triplicate.
Ethical approval: The conducted research is not related to either human or animals use.
3 Results and Discussion
Compound 4 was obtained as a white powder. Its molecular formula was found to be C44H88O2 on the basis of its TOF-MS-ESI+ spectra that showed pseudo-molecular ion peak [M+2NH4++H]+ at m/z = 685.3. The 1H NMR had peaks characteristics of aliphatic esters [22,23,24]. The spectrum revealed the presence of a signal of two protons triplet at δH 4.00 (2H, t, J = 6.7 Hz) probably due to the 2H-1′ deshielded by the proximity of the ester function fixed on the same carbon C-1′, a broad signal between δH 1.20 and 1.33 was attributed to the hydrocarbon chain (CH2)n, this signal showed an integration of 74 protons corresponding to 37 methylene groups. A triplet of six protons at δH 0.81 (6H, t, J = 7.0 Hz) corresponding to two terminal methyl groups was also visible. The 1H NMR spectra also displayed a signal of two protons triplet at δH 2.22 (2H, t, J = 7.5 Hz) attributed to the methylene protons adjacent to the carbonyl group of the ester function. The 13C NMR spectral data indicated characteristic signals of a fatty ester among which a signal of a carbonyl ester function at δC 174.0 attributable to the C-1, a signal of a methylene carbon at δC 64.3 (C-1′) deshielded by the proximity of the ester function, a signal at δC 14.1 corresponding to the terminal methyl groups (C-27 and C-17′). The remaining methylene carbons appeared between δC 22.7 and 31.9 were assigned accordingly. The COSY spectra of compound 4 revealed one spin system associated with the alkane long chain. Thus, the methyls at δH 0.81 (6H, t, J = 7.0 Hz) correlated with a set of protons at δH 1.20 which in turn correlated with the methylene protons at δH 1.54 (m). The correlations of the methylene at δH 1.54 with the ones at δH 2.22 (2H, t, δH = 7.5 Hz) and 4.00 (2H, t, J = 6.7 Hz) respectively were also visible (Figure 2). From the HMBC spectra of compound 4, long range correlations were unambiguously detected between the protons 2H-1′ at δH 4.00 and carbons C-2′ (δC 28.4), C-3′ (δC26.0) and C-1 (δC 174.0) ; methylene protons 2H-2′ (δH 1.54) and carbons C-1′ (δC 64.3), C-3′ (δC 26.0), C-4′ (δC 29.1) and C-1 (δC 174.0). Another set of long range correlations was observed between the methylene at δH 2.22 (2H-2) and C-1 (δC 174.0), C-3 (δC 25.1) and C-4 (δC 29.2) (Figure 2). On the basis of above discussion the structure of compound 4 was elucidated as heptadecyl heptacosanoate. The mass spectral fragmentation was also consistent with the proposed structure. The prominent ion fragments arising at m/z 393.3 [M-C17H35O●]+ and 409.2 [M-C17H35O2●]+ (Figure 3) suggested that heptacosanoic acid was esterified with heptadecanol. The fragment ion arising at m/z 315.2 [C19H38O2+NH4+−H]+ correspond to the loss of hexacosene (C26H52) through a Mc Lafferty rearrangement. Further loss of 113 uma (C8H17●) by this fragment led to the base peak at m/z 185.0.
Nonacosane (1), heptatriacontanol (2), Docosanol (3), D-mannitol (5), D-mannitol acetate (6), and a mixture of β-sitosterol (7), stigmasterol (8) and fucosterol (9) in a ratio of 3:1:2 (estimated from the relative intensities of protons H-22 and H-23 of stigmasterol (8), H-28 of fucosterol (9) and H-6 in 1H-NMR signals), were also isolated and characterized from spectral analysis and comparison with the literature [13,14,15,16,17,18,19].
The antibacterial and anticandidal activities of compounds which were in sufficient amount were investigated using the broth microdilution method. This microdilution method has been adopted because it is less expensive, less cumbersome than the macrodilution method and it yields reproducible results. Bacterial growth could be assessed either visually by grading turbidity or spectrophotomerrically by measuring optical density. The MICs and MFCs of all the tested compounds were determined (Table l). “The tested compounds showed variable antimicrobial activity with MICs values ranging from 32 to 128 μg/mL. D-mannitol (5) and D-mannitol acetate (6) presented the highest antibacterial activities depending on the bacteria strains, while they were inactive (> 128 μg/mL) against all tested yeast strains. These two compounds had the same activities (MIC = 32 μg/mL) against the isolate strains of E. coli and S. typhi. This activity has decreased for D-mannitol acetate (6) against S. typhi ATCC6539 (MIC = 128 μg/mL), and increased against P. aeruginosa ATCC972. The highest antifungal activity (MIC = 128 μg/mL) was recorded for docosanol (3) and the mixture of phytosterols β-sitosterol (7), stigmasterol (8) and fucosterol (9) against all the tested yeast except for C. parapsilosis which was not sensitive to the mixture of phytosterols.
This study conducted on the stem barks of Gardenia aqualla, is a part of our research on the bioactive constituents of the medicinal plant of Cameroon pharmacopeae. G. aqualla is a medicinal plant growing in the Sudano-Guinean savannahs of the country. From the MeOH extract of the plant stem barks, nine compounds were isolated and their structures were elucidated by extensive NMR spectroscopy and Mass Spectrometry. This is the first report on the isolation of compounds from this plant species and to the best of our knowledge, compound 4 is reported here for the first time from plant kingdom, while compounds 1, 2, 3, 6 and 9, are reported here for the first time from the genus Gardenia.
This work was supported by the International Foundation of Science (IFS) Grant No. F/5776-1 awarded to Mr JNN.
Shrestha P.M., and Dhillion S.S. Medicinal plant diversity and use in the highlands of Dolakha district, Nepal. J. Ethnopharmacol., 2003, 86, 81-96. Google Scholar
Hostettmann K., Marston A., Ndjoko K., Wolfender J.-L., 2000. The potential of African plants as a source of drugs. Curr. Org. Chem., 2000, 4, 973-1010. Google Scholar
Misganaw T., Alemayehu Y., and Negera A. Assessment of Antibacterial Activities and Phytochemical Screening of Leaf and Fruit of Solanum marginatum. J. Biol. Chem. Res., 2015, 32(2), 966-971. Google Scholar
Arbonnier M., Arbres, arbustes et lianes des zones sèches ďAfrique de ľOuest. Editions Quae/MNHN, France, 2009. Google Scholar
Burkill H.M., Useful plants of West Tropical Africa. Edinburgh: Royal Botanic Garden, 1985. Google Scholar
Jiofack T., Ayissi L., Fokunang C., Guedje N., Kemeuze V., Ethnobotany and phytomedicine of the upper Nyong valley forest in Cameroon, Afr. J. Pharm. Pharmacol., 2009, 3(4), 144–150. Google Scholar
Oluranti A.C., Michael U.O., Jane U.-O.C., Ayembe N.A., Ethno botanical studies of medicinal plants used in the management of Peptic ulcer disease in Sokoto State, North Western Nigeria, Int. Res. J. Pharm. Pharmacol., 2012, 2(9), 225-230. Google Scholar
Awede B., Houetchegnon P., Djego J.G., Djrolo F., Gbenou J., Laleye A., Effects of Lophira lanceolata and of Three Species of Gardenia Leaves Aqueous Extracts on Blood Glucose and Lipids in Wistar Rat, J. Physiol. Pharm. Adv., 2015, 5(10), 757-765. CrossrefGoogle Scholar
Nethengwe M.F., Opoku A.R., Dludla P.V., Madida K.T., Shonhai A., Smith P., et al., Larvicidal, antipyretic and antiplasmodial activity of some Zulu medicinal plants, J. Med. Plant. Res., 2012, 6(7), 1255-1262. Google Scholar
Simo T.R., Telefo B.F., Nyemb J.N., Yemele D.M., Njina S.N., Goka S.M.C., et al., Anticancer and antioxidant activities of methanol extracts and fractions of some Cameroonian medicinal plants. APJTM., 2014, 7, S442-S447. Web of ScienceGoogle Scholar
Njinga N.S., Sule M.I., Pateh U.U., Hassan H.S., Usman M.A., Bilkisu A., et al., Phytochemical and antimicrobial activity of stem-bark of Gardenia aqualla Stapf and Hutch (Rubeacea), J. Med. Plants Res., 2014, 8(27), 942-946. CrossrefGoogle Scholar
Tripathi S.K., Asthana R.K., Ali A., Isolation and characterization of 5-ethylhentriacontane and Nonacosane from Salvia plebeian. Asian J. Chem., 2006, 18, 1554-1556. Google Scholar
Gohar A.A., Heptatriacontanol and phenolic compounds from Halochris hispida. OJBS, 2001, 1(9), 843-845. Google Scholar
De Almeida B.C., Araújo B.Q., Barros E.D.S., Freitas S.D.L., Maciel D.S.A., Ferreira A.J.S., et al., Dammarane Triterpenoids from Carnauba, Copernicia prunifera (Miller) H. E. Moore (Arecaceae), Wax. J. Braz. Chem. Soc., 2017, 28(8), 1371-1376. Google Scholar
Branco A., Santos J.D.G., Pimentel M.M.A.M., Osuna J.T.A., Lima L.S., David J.M., D-Mannitol from Agave sisalana biomass waste. Ind. Crops and Prod., 2010, 32, 507–510. CrossrefWeb of ScienceGoogle Scholar
Sheng Z., Dai H., Pan S., Wang H., Hu Y., Ma W., Isolation and Characterization of an α-Glucosidase Inhibitor from Musa spp. (Baxijiao) Flowers. Molecules, 2014, 19, 10563-10573. Google Scholar
Ahmed Y., Rahman S., Akhtar P., Islam F., Rahman M., Yaakob Z., Isolation of steroids from n-hexane extract of the leaves of Saurauia roxburghii. IFRJ, 2013, 20(5), 2939-2943. Google Scholar
Majik M.S., Adel H., Shirodkar D., Tilvi S., Furtado J. Isolation of Stigmast-5,24-dien-3-ol from marine brown algae Sargassum tenerrimum and its antipredatory activity. RSC Adv., 2015, (5), 51008-51011. Web of ScienceGoogle Scholar
Nyemb J.N., Tchinda T.A., Talla E., Nanga E.B., Ngoudjou T.D., Henoumont C., et al., Vitellaroside, a new cerebroside from Vitellaria paradoxa (Sapotaceae) and its bioactivities, Nat. Prod. Chem. Res., 2018, 6, 306. . CrossrefGoogle Scholar
Dzoyem J.P., Tchuenguem T.R., Kuiate J.R., Teke N.G., Kechia FA., Kuete V., In Vitro and in vivo antifungal activities of selected Cameroonian dietary spices, BMC Complementary and Alternative Medicine, 2014, 14(58), 1-8. Google Scholar
Najib S., Ahamad J., Ali M., Mir S.R., Isolation and characterization of fatty acid esters from the seeds of Cichorium intybus, AJPCT, 2014, 2(4), 469-473. Google Scholar
Talla E., Daouda D., Nyemb J.N., Sophie L., Vander E.L., Dabole B., et al., Two new compounds from stem barks of Vepris heterophylla (Engl.) R. Let. (Rutaceae), J. Chem. Pharm. Res., 2015, 7(7), 553-557. Google Scholar
About the article
Published Online: 2018-05-08
Conflict of interest: Authors state no conflict of interest.
Citation Information: Open Chemistry, Volume 16, Issue 1, Pages 371–376, ISSN (Online) 2391-5420, DOI: https://doi.org/10.1515/chem-2018-0035.
© 2018 Jean Noël Nyemb et al., published by De Gruyter. This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License. BY-NC-ND 4.0