Chemical Composition and Cytotoxic Activity of the Essential Oil and Oleoresins of In Vitro Micropropagated Ansellia africana Lindl: A Vulnerable Medicinal Orchid of Africa.

Orchids are rich treasure troves of various important phytomolecules. Among the various medicinal orchids, Ansellia africana stands out prominently in the preparing of various herbal medicines due to its high therapeutic importance. The nodal explants of A. africana were sampled from asymbiotically germinated seedlings on basal Murashige and Skoog (MS) medium and were micropropagated in MS medium supplemented with 3% sucrose and 10 µM meta topolin (mT) + 5 µM naphthalene acetic acid (NAA) +15 µM indole butyric acid (IBA) + 30 µM phloroglucinol (PG). In the present study, the essential oil was extracted by hydrodistillation and the oleoresins by the solvent extraction method from the micropropagated A. africana. The essential oil and the oleoresins were analysed by Gas Chromatography (GC) and GC/MS (Mass spectrometry). A total of 84 compounds were identified. The most predominant components among them were linoleic acid (18.42%), l-ascorbyl 2,6-dipalmitate (11.50%), linolenic acid (10.98%) and p-cresol (9.99%) in the essential oil; and eicosane (26.34%), n-butyl acetate (21.13%), heptadecane (16.48%) and 2-pentanone, 4-hydroxy-4-methyl (11.13%) were detected in the acetone extract; heptadecane (9.40%), heneicosane (9.45%), eicosane (6.40%), n-butyl acetate (14.34%) and styrene (22.20%) were identified and quantified in the ethyl acetate extract. The cytotoxic activity of essential oil and oleoresins of micropropagated A. africana was evaluated by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium Bromide) assay on Vero cells compared to the standard drug doxorubicin chloride. The present research contains primary information about the therapeutic utility of the essential oil and oleoresins of A. africana with a promising future research potential of qualitative and quantitative improvement through synchronised use of biotechnological techniques.

Isolation, identification and molecular docking studies of a new isolated compound, from Onopordon acanthium: a novel angiotensin converting enzyme (ACE) inhibitor.

ETHNOPHARMACOLOGICAL RELEVANCE: Onopordon acanthium (also known as Scotch thistle) is a medicinal plant of the Asteraceae family that is widely distributed in Europe and Asia. This plant has been long used in traditional medicine as a hypotensive, cardiotonic and diuretic agent. AIM OF THE STUDY: The present study is designed to isolate an active compound with ACE inhibition activity from O. acanthium, measure antioxidant activity, predict domain specificity and pharmacokinetic properties of the isolated compound. MATERIALS AND METHODS: Methanolic extract of O. acanthium seeds, has been subjected to a repeated column chromatography to give a pure compound with Angiotensin Converting Enzyme (ACE) inhibition activity. The ACE inhibition activity was determined using hippuryl-L-histidyl-L-leucine (HHL) as substrate in an in vitro ACE assay. Structure of the pure compound, isolated from O. acanthium has been established by spectroscopic methods, including Infrared (IR), Nuclear Magnetic Resonance (NMR) and Mass spectrum analysis. In addition, antioxidant activity of the new isolated compound, was measured using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay and compared with those of BHT and Trolox as positive controls. Enzyme type inhibition and ACE-C or N domain specificity of the new compound was further evaluated through molecular modeling and docking studies. RESULTS: Structure of the pure compound, isolated from O. acanthium (83±1% ACE inhibition activity at concentration of 330 µg/ml), has been established. The isolated compound possessed acceptable antioxidant activity (IC50 value of 2.6±0.04 µg/ml) in comparison with BHT (IC50 value of 10.3±0.15 µg/ml) and Trolox (IC50 value of 3.2±0.06 µg/ml). Molecular docking predicted competitive type enzyme inhibition and approximately similar affinity of the isolated compound for ACE-C and N domains. CONCLUSION: The results derived from computational and in vitro experiments, confirm the potential of the isolated compound, from O. acanthium as a new antihypertensive compound and give additional scientific support to an anecdotal use of O. acanthium in traditional medicine to treat cardiovascular disease such as hypertension.

[Chemical constituents in root of Zanthoxylum nitidum].

OBJECTIVE: To study the chemical constituents of Zanthoxylum nitidum. METHOD: Column chromatography on Silica gel and Sephadex LH - 20, and recrystallization were applied for the isolation and purification of the constituents. The structures were elucidated on the basis of spectral analysis, chemical evidences and by comparison with the data reported in literature. RESULT: From the CHCl3 fraction and n-butanol fraction of the EtOH extract of the roots of Z. nitidum, 10 compounds were isolated and identified as 2, 4-dihydroxypyrimidine (1), syringic acid (2) , 2, 6-dimethoxy-1, 4-benzoquinone (3) , 4-hydroxybenzoic acid (4), ethylparaben (5), (Z)-3-(2, 3, 4-trimethoxyphenyl) acrylic acid (6), 5, 6, 7-trimethoxycoumarin (7), stigmast-9 (11) -en-3-ol (8), daucosterol (9), beta-sitosterol (10). CONCLUSION: Compounds 1-9 were isolated and identified from the roots of Z. nitidum for the first time. Furthermore, we note here the first isolation of compound 6 as a natural product.

Acryloylated glucose 3-nitropropanoates from Indigofera kirilowii.

Two unique glucose esters of 3-nitropropanoic acid with acryloyl moieties, kirilowin A and kirilowin B, were isolated from the roots of Indigofera kirilowii. Their structures were elucidated by detailed spectroscopic analysis. The two acrylates constitute new additions to the toxic glucose conjugates of 3-nitropropanoic acid in angiosperms.

[Studies on chemical constituents from root of Hedysarum polybotrys].

OBJECTIVE: To study the chemical constituents of Hedysarum polybotrys. METHOD: Chromatographic methods were used to isolate compounds from H. polybotrys and chemical and spectral methods were used to elucidate the structures of the isolated compounds. RESULT: Five compounds, N,N,N-trimethyl-tropaphone inner salt (hypaphorine) (1), octadecyl-3-methoxy-4-hydroxy-benzeneacrylate (2), 5,7,4'-trihydroxy-dihydroflavanone 5,7-di-O-beta-D-glucopyranoside (3), 3,4,5-trimethoxy cinnamic acid methy ester (4) and vanillic acid (5), were isolated from the roots of H. polybotrys. CONCLUSION: Compounds 1, 2 and 3 were obtained from this plant for the first time, while compounds 1 and 2 were isolated from Hedysarum for the first time.

[Studies on chemical constituents of Bletilla striata (Thunb) Reichb. f].

OBJECTIVE: To study the chemical constituents of Bletilla striata. METHOD: The constituents were separated and purified by column chromatography with silica gel, and identified by NMR, MS and physical data. RESULT: Three compounds were isolated and identified as hexacosanoic alcohol 3-(4-hydroxy-3-methoxybenzol)-trans-acryliceylenate(1), physcion(2) and cyclobalanol(3). CONCLUSION: Compound 1 was a new compound and compound 3 was isolated from this plant for the first time.

Melithiazols, new beta-methoxyacrylate inhibitors of the respiratory chain isolated from myxobacteria. Production, isolation, physico-chemical and biological properties.

New antibiotic compounds, melithiazols, were isolated from the culture broth of strains of the myxobacteria Melittangium lichenicola, Archangium gephyra, and Myxococcus stipitatus. The compounds belong to the group of beta-methoxyacrylate (MOA) inhibitors and are related to the myxothiazols. The melithiazols show high antifungal activity, but are less toxic than myxothiazol A and its methyl ester in a growth inhibition assay with mouse cell cultures. The melithiazols inhibit NADH oxidation by submitochondrial particles from beef heart. Melithiazol A blocks the electron transport within the bc1-segment (complex III) and causes a red shift in the reduced spectrum of cytochrome b.

Production of methyl 3-oxoartemisinate from methyl artemisinate by suspension cell culture of Mentha piperita.

Methyl artemisinate was fed to the suspension cell culture of Mentha piperita. The biotransformation product was isolated and identified as a novel compound, methyl 3-oxoartemisinate. The Mentha cells were apparently capable of extensively oxidizing at the allylic C-3 position, to give rise to an oxo group. The conversion of the fed methyl ester of the acid reached a maximum in 48 h with 5.5% conversion. The physicochemical data of the oxo compound are presented.

Two new aromatic constitutents from the rootwood of Aeschynomene mimosifolia.

The rootwood of Aeschynomene mimosifolia Vatke (Leguminosae) has yielded a new neoflavonoid, mimosifoliol (1), and an unusual C16-styrylcycloheptenone derivative, mimosifolenone (2). The structures of these compounds were determined on the basis of spectral analysis. Compound 1 demonstrated weak activity in DNA-strand scission assay, while compound 2 was found to be inactive. Mimosifoliol (1) was inactive toward several human cell lines, while 2 was moderately active against the KB cell line.

Natural antimutagenic agents.

Following a brief review of recent discoveries in the field of natural antimutagenic and tumor chemopreventive agents, contemporary findings in the author's laboratories employing the direct acting mutagen, ethyl methanesulfonate, in modified Ames tests and eukaryotic murine FM3A mammary tumor cells modified to be subject to thymidine-less death are described to illustrate the underlying principles. The EMS studies are illustrated with the isolation of the novel antimutagen, plicatin B, from the medicinal plants, Psoralea juncaea and P. plicata. The FM3A studies are carried out with extracts of Styrax asiatica, a plant previously studied extensively with the EMS system. The FM3A findings closely parallel the earlier work with EMS showing that the responsible agents, cinnamic acid, cinnamoyl ricinoleate and cinnamoyl cinnamate are effective both in prokaryotic and eukaryotic tests and that the new FM3A assay system has useful properties for screening and assay of novel antimutagenic agents.