Prenylation of aromatic secondary metabolites is an important process involved in the biosynthesis of many biologically active compounds in plants and animals. Many prenylated natural products have been shown to exhibit very good anti-tumor, anti inflammatory and antimicrobial activities. The addition of prenyl side chain to an aromatic secondary metabolite often affects its pharmacological activity. The aim of this review is to examine the influence of the prenyl side chain on the pharmacological activities of some classes of aromatic secondary metabolites and the potential application of prenylation in the development of novel drugs

The aim of this study seeks to investigate the presence of steroids, triterpenes, alkaloids, saponins, tannins, anthraquinones and flavonoids compounds as the possible agent responsible for the medicinal activities of the leaf of the plant Paullinia pinnata and also to carry out phytochemical screening of the dried leaf of the plant, to extract and fractionate the leaf and finally to carry out thin layer chromatography of the different fractions. In the phytochemical investigation of the plant, the powdered leaves was tested positive for steroids, triterpenes, alkaloids, saponins, tannins, anthraquinones and flavonoids. The presence of the constituents was also found to be similar to those reported for most medicinal plants. In East Africa, the leaves are used against snake bites, rabies, mental problems, blindness and eye troubles, together with the roots, against gonorrhoea, paralysis, wounds, threatened abortion, malaria, ancylostomiasis, and to expel placenta. Roots are applied against eczema, as a tonic and as a styptic medicine.

Neocarya macrophylla belongs to the Chrysobalanaceae family and is extensively used in folk medicine as an antibacterial, antivenin, antiasthmatic, anticancer, analgesic and anti-inflammatory agent. This study was aimed at isolation and characterization of compounds from the stem bark of Neocarya macrophylla. Pulverized plant material was exhaustively extracted with methanol using maceration method and concentrated invacuo with the aid of rotary evaporator at 40 o C to afford a reddish brown crude methanol extract (ME). The methanol extract was successively partitioned into hexane, dichloromethane, ethylacetate, n-butanol and aqueous fractions. Stigmasterol was isolated from the hexane fraction and a catechin glycoside, Bis-(5,7-diacetyl-catechin-4'-α-rhamnopyranoside) was isolated from the ethylacetate soluble fraction using a combination of silica gel column, gel filtration (sephadex LH-20) and preparative thin layer chromatography. The structures of the compounds were established on the basis of chemical tests, spectroscopic analysis and by comparison with reference spectral data.

Background: Natural products play a significant role in human therapy. They represent a huge reservoir of bioactive chemical diversity and help in understanding the cellular pathways that are essential component of drug discovery process. Objective: This study was aimed at evaluating the antimicrobial activity of stigmasterol isolated from the stem bark of Neocarya macrophylla. Methods: Stigmasterol previously isolated from the stem bark of N. macrophylla was subjected to antimicrobial screening against methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), S. aureus, Streptococcus faecalis, Escherichia coli, Salmonella typhimurium, Pseudomonas fluorescens, Klebsiella pneumoniae, Candida albicans and Candida krusei using agar diffusion and broth dilution methods. Results: Susceptibility test results showed that the compound (100 μg/mL) inhibited the growth of all the test organisms with mean zone of inhibition range from 23 mm to 30 mm except the VRE, S. typhi and K. pneumoniae. The activity of stigmasterol was compared with that of ciprofloxacin (5 μg/mL), the standard antibacterial drug, and fluconazole (5 μg/mL), the antifungal agent. The test compound displayed a broad-spectrum of activity, and in many cases exhibited comparable antibacterial activity when compared to ciprofloxacin. Interestingly, the compound also showed antifungal activity against Candida spp., affording comparable inhibitory effect as fluconazole. The minimum inhibitory concentration (MIC) and the minimum bactericidal/fungicidal concentration (MBC/MFC) of stigmasterol range from 6.25 μg/mL to 25 μg/mL and from 12.5 μg/mL to 50 μg/mL, respectively. Conclusion: These properties suggest that the isolated stigmasterol is a potent and broad-spectrum antibacterial and antifungal agent and as such may serve as a lead compound in the development of novel antimicrobial drugs.

Entada africana (Ea, Asteraceae) has been widely used traditionally to treat different ailments, as food, insecticides, source of gums, in some small carpentry works. Studies on the pharmacognostic characterization, nutritional, elemental and physicochemical contents has been reported. In vivo and in vitro studies on the plant validated some ethnomedicinal claims of the use of the plant as an anti-inflammatory, analgesic, antibacterial, antioxidant, antiviral, anti-angiogenic, cytotoxic agents among others. Triterpenes, saponins, flavonoids and sugars were reported as bioactive constituents which might be responsible for the aforementioned pharmacological actions of the plant.However, more researches are required in order to isolate bioactive compounds from the different parts of Ea and evaluate their effects on different ailments.