Records of Natural Products Articles

The steam distilled volatile oil obtained from dried Lippia multiflora Moldenke was examined by gas chromatography-mass spectrometry (GC-MS).  The major components were 1,8-cineole (60.5%), sabinene (16.9%), α-terpineol (14.1%) and α-pinene (4.4%).  The oil displayed no antibacterial activity against either gram positive Bacillus cereus or Staphylococcus aureus or gram negative Escherichia coli, (MIC = 1250 µg/mL).  A cluster analysis was performed for comparison and characterization of L. multiflora essential oil from Nigeria with other oils reported in the literature from different locations across central Africa, and reveals much chemical variation in this species with at least 13 different chemotypes.

A simple, fast and precise quantitative high performance thin-layer chromatographic method has been developed for quantitative estimation of α-mangostin in fruit pericarp of Garcinia mangostana L. (Hypericaceae). Best solvent for extraction of a-mangostin optimized after screening with five solvents under same conditions using hot solid-liquid extraction through soxhlet apparatus. Methanol and chloroform gave highest and second highest recovery of a-mangostin, respectively. Plates were developed in chloroform-methanol in the ratio of 27-3 (v/v). Post-chromatographic derivatization performed using anisaldehyde-sulphuric acid reagent and scanned at 382 nm in ultraviolet-visible mode. The developed method was found to be linear in the range 1.0 to 5.0 mg spot-1, limits of detection and quantitation were 150 and 450 ng spot-1. The developed method was validated in terms of system suitability, specificity and robustness.

The antidiabetic and antilipidemic effects of Bougainvillea glabra was investigated in this study using 25 male wistar rats. The rats were divided into 5 groups comprising of five animals each. These groups include a normal control (administered saline), an extract control (administered 100 mg/kg of extract) and a diabetic control (untreated group). The remaining two groups were administered 100mg/kg and 400 mg/kg of the extract respectively. The study lasted for three weeks although blood samples were obtained from the rat tails after every week. The results show that the extract significantly (p< 0.05) reduced the hyperglycaemia from 12±0.40 mmol/L (Diabetic Control) to 4.04±0.03 mmol/L (400 mg/kg group). Likewise, the extract significantly reduced the Total Cholesterol (TC), Triglyceride (TG) and Low-Density Lipoprotein Cholesterol (LDL-Cholesterol), while increasing the High-Density Lipoprotein Cholesterol (HDL-C). In conclusion, the observations from this study show that Bougainvillea glabra has antidiabetic effect  and beneficial effects on blood lipid profile, thus justifying the use of the plant by traditional medicine practitioners for the treatment of diabetes mellitus.

The study of the chemical constituents of the whole plant of Geranium wallichianum (Geraniaceae) has resulted in the isolation and characterization of six compounds. These six compounds were identified as ursolic acid (1), β-sitosterol (2), stigmasterol (3),b-sitosterol galactoside (4), herniarin (5), and 2,4,6-trihydroxyethylbenzoate (6) which were isolated for the first time from Geranium wallichianum. The above compounds were individually identified by spectroscopic analyses and comparisons with reported data. The antioxidant potential of Geranium wallichianum extracts has been investigated by DPPH radical scavenging assay and EtOAc extract was found to be most potent with IC50 19.05 ug/mL.

Phytochemical investigations were performed in two plant species used in Sudanese traditional medicines to treat different illnesses, Diospyros mespiliformis and Croton zambesicus. The investigations revealed compounds of triterpenes (lupane series), one trihydroxyflavone and one diterpene. The compounds have been isolated and identified using various chromatographic and spectroscopic techniques. These were lupeol (1), betulinic acid (2), betulin (3) and lupenone (4) from Diospyros mespiliformis. Compounds 1, 2, 3 in addition to diterpene ent -kaurane-3β, 16β, 17-triol (5) and vitexin (6) were re-isolated from Croton zambesicus. However,compound 5 and 6 were isolated for the first time from this source.The pure isolated compounds and semi-synthesized acetates 1Ac, 2Ac and 3Ac, which were prepared from compounds 1, 2 and3 respectively, were subjected to two bioassays: α- glucosidase enzyme inhibition assay and antioxidant activity. Compounds, 1, 1Ac, 3 and 4 showed a marked α-glucosidase inhibitory potential, while compound 6exhibited strong antioxidant activity.

Curvularia oryzae MTCC 2605 was exploited for the production of secondary metabolites. The major compounds from the crude extract were purified by silica gel column chromatography and identified to be 11-α-methoxycurvularin and (S)-5-ethyl-8, 8-dimethylnonanal by NMR and Mass spectral data. Bioassays showed that 11-α-methoxycurvularin was active against bacteria, fungi and 4th instar Spodoptera litura larvae.