Caroline Langat-Thoruwa

A new naphthalene derivative, named eucleanal (1), was isolated from Euclea divinorum Hiern., and its structure elucidated by detailed spectroscopic (¹H, ¹³C NMR, COSY, HMQC, HMBC) and HREIMS analysis.

A new flavone dimer, drypetdimer A (1), was isolated from Drypetes gerrardii J. Hutch. The structure of the new compound was elucidated by detailed spectroscopic analysis such as ¹H, ¹³C NMR, COSY, HMQC, HMBC and HREIMS.

SUMMARY The present paper discusses the effects of the crude extracts of Trichoderma spp. on a number of fungal and bacterial organisms. These include Paecilomyces variotii, Penicillium notatum, Nematospora corylii, Mucor miehei, Bacillus brevis, Bacillus subtilis, Enterobacter dissolvens and Sarcina lutea. The culture broth extracts of different isolates of Trichoderma harzianum, T. longibrachiatum and T. koningii cultured in different media were investigated individually for in-vitro antifungal and antibacterial activities by agar diffusion technique. The culture broth extracts of T. harzianum produced definite antifungal and antibacterial activities against most of the test organisms. The results indicate that the extracts were fungicidal and antibacterial at a concentration of 100 µg per 6mm paper disks. Trichoderma harzianum showed the highest activity while T. koningii showed the least activity against most of the test organisms especially the yeast Nematospora coryli. The results of this study indicate that the Trichoderma species especially T. harzianum is a possible source of useful antimicrobial agents against pathogenic microorganisms which include gram-negative, gram-positive, fungi and yeasts. African Journal of Health Sciences Vol.11(1&2) 2004: 33-42

Sixty organic and aqueous extracts of eleven plants used for the control of malaria by local communities in Kisii District, Kenya were screened for in vitro anti-plasmodial activity. The plants selection was based on existing ethnobotanical information and interviews with local communities. The extracts were tested against chloroquine sensitive and resistant laboratory adapted strains of Plasmodium falciparum. The study revealed that 63.6% of the plants were active (IC₅₀ ≤ 100 µg/mL). Extracts of four plants, Ekebergia capensis, Stephania abyssinica, Ajuga remota and Clerodendrum myricoides gave IC₅₀ values below 30 µg/mL against both chloroquine sensitive and resistant P. falciparum strains. Combination of extracts of E. capensis and C. myricoides with chloroquine against the multi-drug resistant P. falciparum isolate (V1/S) revealed synergistic effect. The plants which showed activity may be useful as sources for novel anti-plasmodial compounds. Copyright © 2004 John Wiley & Sons, Ltd.

Bioactive metabolites from Trichoderma harzianum and Trichoderma longibrachiatum