Chemical constituents from Cordia myxa L. (Boraginaceae) and their antibacterial activity.

Chemical investigation of Cordia myxa L. (Boraginaceae) resulted in the isolation of the following ten known compounds: 1-naphthaleneacetic-5-carboxy-1,2,3,4,4a,7,8,8a-octahydro-1,2,4a-trimethyl-[1S-(1α,2ß, 4a,8aα)]-acid (1), hexacosanoate-1-glyceryl (2), 3ß-urs-12,20(30)-diene-27,28-dioic acid (3), 3ß-D-glucopyranosylurs-12,20(30)-diene-27,28-dioic acid (4), stigmasterol (5), stigmasterol-3-O-ß-D-glucopyranoside (6), oleanolic-acid (7), 3-O-acetyl-oleanolic acid (8), betulin (9) and spinasterol-3ß-O-D-glucopyranoside (10). The isolated compounds were characterised by using spectroscopic methods, 1D and 2D NMR, mass spectroscopy (ESI-MS) and by comparison with the literature data. To the best of our knowledge, compounds 1, 3, 4, 8 and 10 were isolated for the first time from the Cordia genus. This result improves the chemotaxonomy knowledge of the Cordia genus. The antibacterial activities were performed by the Muller-Hinton agar diffusion method. The antibacterial activities were studied on Salmonella typhi, Staphylococcus aureus, Vibrio cholerae, Pseudomonas aeruginosa and Escherichia coli ATCC 25922. Compounds 8 and 9, at 20.0 mg/mL resulted to be effective antimicrobial against E. coli, V. cholerae and P. aeruginosa.

Ternifoliasaponin, a new triterpenoid saponin from the roots of Gardenia ternifolia Schumach & Thonn (Rubiaceae).

A new triterpenoid saponin, Ternifoliasaponin (1), together with four known compounds (2-5) chikusetsusaponin IVa (2), chikusetsusaponin IVa methyl ester (3), bonushenricoside B (4) and Dianoside C (5) were isolated from roots of Gardenia ternifolia Schumach. & Thonn (Rubiaceae). The structures of isolated compounds were elucidated on the basis of spectroscopic analysis and chemical methods. The antibacterial activities of compounds (3), and (4) were performed by the Muller-Hinton agar diffusion method. The antimicrobial activities of the compounds were studied on Salmonella typhi (Enterobacteriaceae), Staphylococcus aureus and Pseudomonas aeruginosa microorganisms. Compound (3) at 25 mg/mL, showed moderately sensitive effect (8.0 ˂ DIZ ˂14.0 mm) on S. typhi, S. aureus and P. aeruginosa. Compound (4) at 25 mg/mL and compound (3) at 12.5 mg/mL exhibited moderately sensitive effect on S. typhi and S. aureus. Compound (4) inhibited moderately sensitive the S. typhi and P. aeruginosa colonies at 12.5 mg/mL.

Cholinesterase, α-glucosidase, tyrosinase and urease inhibitory activities of compounds from fruits of Rinorea oblongifolia C.H. Wright (Violaceae).

From Rinorea oblongifolia fruits, 3-Nor-4ß-friedelan-24-ol (1) and 3-decyl-6,7,8-trimethoxy-2H,5H-furo[4,3,2-de]isochromene-2,5-dione (4), new derivatives alongside, 28-hydroxyfriedelan-3-one (2), friedelin (3), 3,3',4,4',5'-pentamethylcoruleoellagic acid (5), hexamethylcoruleoellagic acid (6), 3',4,4',5,5'-pentamethylcoruleoellagic acid (7), and fatty compounds 8-11 were isolated and characterized using HRESIMS, EIMS, 1D and 2D NMR. In vitro enzyme inhibition of compounds 1, 2, 4, 5, 6 and 7 were evaluated on acetylcholinesterase (AChE), butyrylcholinesterase (BChE), α-glucosidase, urease and tyrosinase. Against AChE and BChE, the phenolic compounds 4, 5, 6, and 7 had good activity probably due to the phenolic nature and methoxy substituents. Compounds 4, 5, 6 and 7 exhibited good α-glucosidase inhibition especially compound 4 whose IC50 = 42.45 ± 0.46 µg/mL was close that of acarbose (IC50 = 20.52 ± 0.84 µg/mL) standard drug. Urease and tyrosinase were appreciably inhibited by the compounds. Overall results of enzyme inhibitory assays indicate Rinorea oblongifolia, fruits and its constituents as potential remedy for enzymatic disorders.

In vitro α-glucosidase inhibitory activity of isolated compounds and semisynthetic derivative from aerial parts of Erythrina senegalensis DC.

The current study was conducted to isolate the phytoconstituents from Erythrina senegalensis leaves and stem bark and evaluate their inhibitory activity against α-glucosidase, digestive enzyme related to diabetes mellitus. Phytochemical investigation of the leaves resulted in the isolation of three saponins (3-5), two triterpenoids (7 and 8) and two steroids (10a and 10b) as inseparable mixture, while one saponin (6), one triterpenoid (9) and one mixture of two cinnamates (2a and 2b) were isolated from the stem bark. Except for compounds 2 b, 7, 8, 10a and 10 b all the isolated compounds are reported here for the first time from the genus Erythrina. Acetylation of the mixture of two cinnamates (2a and 2b) led to a new diester derivative (1) trivially called erythrinamate. The extracts and pure compounds (3, 4, 6) showed good α-glucosidase inhibitory activity compared to the standard drug acarbose. The findings suggest that saponins of E. senegalensis could be used to develop potential anti-hyperglycemic drugs.

A novel pentacyclic triterpene acid from the stem barks of Combretum fragrans F. Hoffm (Combretaceae).

A phytochemical study was carried out on stem bark of Combretum fragrans F. Hoffm., a medicinal plant belonging to the Combretaceae family and used traditionally in the treatment of various ailments. Column chromatography separation on silica gel of the crude methanol extract from stem barks of C. fragrans led to the isolation of a new pentacyclic triterpene acid, with a 3,6-epoxide bridge and trivially named as fragransinic acid (1), along with four known compounds: betulin (2), betulinic acid (3), bellericagenin B (4) and a mixture of ß-sitosterol (5) and stigmasterol (6). Structures were elucidated by extensive spectroscopic analyses including 1D and 2D NMR, mass spectrometry as well as by comparison with literature data. The above compounds were isolated for the first time from C. adenogonium. Implications for chemosystematics and traditional medicine were briefly discussed.

Antimicrobial and α-glucosidase inhibitory activities of chemical constituents from Gardenia aqualla (Rubiaceae).

An aliphatic alkene namely pentapentacontene (4) was isolated for the first time from a natural source, Gardenia aqualla, along with fourteen other compounds including nonacosanol (1), tetratriacontanol (2), octatriacontanol (3), ß-sitosterol (5) and stigmasterol (6), daucosanol (7), ursolic acid (8), uvaol (9), 3ß,19α,23ß,24α-tetrahydroxyurs-12-en-28-oic acid (10), lupenone (11), oleanolic acid (12), vanillin (13), vanillic acid (14) and D-mannitol (15). α-glucosidase inhibitory assay revealed that MeOH and EtOAc extracts of leaves had the best activity with IC50 of 9.65 and 20.03 µg/ml respectively. All the tested compounds showed dose dependent inhibition of α-glucosidase and some of them were found to be comparable to acarbose. Compound 10 was the most potent with IC50 = 1.72 µM. It also showed the most interesting antibacterial activity, against the isolate strain of S. typhi and P. aeruginosa and also exhibited the most significant antifungal activities against all the tested yeasts.

Anticancer and antioxidant activities of methanol extracts and fractions of some Cameroonian medicinal plants.

OBJECTIVE: To obtain a scientific basis of the use of plant-derived preparations by many rural people in Cameroon, for their primary health care needs in the treatment of diseases such as cancer. METHODS: The antiproliferative effect of 11 plants methanol crude extracts on four cancer cells using sulforhodamine-B assay and their antioxidant activities using 1-diphenyl-2-picrylhydrazyl radical and nitric oxide radical scavenging ability were investigated. The Ekebergia senegalensis (E. senegalensis) and Protea elliotii (P. elliotii) extracts were selected based on their antioxidant and anticancer activities, and partition in hexane, dichloromethane, ethyl acetate, butanol and methanol was done. Each fraction was submitted to antioxidant and anticancer activities, and the effect of the dichloromethane fraction (the most antiproliferative fraction) on NCI-H460 cell cycle was determined by flow cytometry. RESULTS: The most antiproliferative substances were found for the extracts from E. senegalensis, P. elliotii, Terminalia macroptera and Vitellaria paradoxa. Whereas the most antioxidant substances were found for the extracts from Cissus populnea, E. senegalensis, P. elliotii, Terminalia macroptera, Vitellaria paradoxa, and Gardenia aqualla. Dichloromethane fraction of P. elliotii was found to be highly antiproliferative to NCI-H460 cancer cells and showed S phase arrest cell cycle progression. Ethyl acetate n-butanol and methanol fractions showed quite strong antioxidant activity for both E. senegalensis and P. elliotii, as compared to that of gallic acid. CONCLUSIONS: Overall, the antiproliferative and antioxidant activities of some of the extracts lend some support to their use in the traditional medicine of Adamawa Region, Cameroon to treat cancer.

Strychnobaillonine, an unsymmetrical bisindole alkaloid with an unprecedented skeleton from Strychnos icaja roots.

A reinvestigation of the roots of Strychnos icaja resulted in the isolation of a new bisindole alkaloid named strychnobaillonine (1) with original C-17-N-1' and C-23-C-17' junctions, in addition to sungucine, bisnordihydrotoxiferine, and strychnohexamine (2). Compound 1 showed potent activity against the chloroquine-sensitive 3D7 strain of Plasmodium falciparum in vitro with an IC50 value of 1.1 µM. The structures of the compounds were defined by detailed spectroscopic analyses, especially 1H and 13C NMR, DEPT, HSQC, COSY, NOESY, HMBC, and HRESIMS. The proposed absolute configuration was based on biosynthetic considerations and spectroscopic data (CD, NMR) supported by molecular modeling.