Effects of collection time on the antimicrobial activities of Harpephyllum caffrum bark

Three collections of Harpephyllum caffrum bark were made from the same female tree in the Eastern Cape during 2003/2004 and tested for antibacterial and antifungal activity. The highest antibacterial activity was detected with plant material collected in June 2003 and December 2003, with a decline in activity in extracts collected in September 2004. Highest antifungal activity was detected in plant material collected in December 2003. TLC analysis revealed some variation in chemical composition of each of the H. caffrum bark extracts tested. The bioautography showed a number of clear zones against a pink background. These clear zones give an indication of antibacterial activity by compounds present in these areas. Bacterial inhibition was visible in all the tested extracts and most of the activity was detected at the point of extract application.