Anti-Mycobacterium phlei Activity of the Bark of Ziziphus talanai (Blanco) Merrill

The bark of Ziziphus talanai (Blanco) Merrill, a tree endemic to the Philippines, is traditionally used in Antique to cure kidney problems such as urinary tract infections (UTI), and skin diseases such as scabies and ringworm. Its antimicrobial activity was screened against several microorganisms to have a more comprehensive anti-infective profile of the plant. The MeOH extract of Z. talanai bark exhibited antimicrobial activity against Gram-positive Mycobacterium phlei, S. aureus and B. subtilis at 20,000 mu g and 2,000 mu g but was inactive against Gram-negative E. coli, P aeruginosa, C. albicans and S. cerevisiae. It has minimal antifungal activity against T mentagrophytes. The MeOH extract of Z. talanai is therefore inactive against uncomplicated UTI, which is mostly caused by E. coli. Further bioassay-guided isolation and subsequent spectral analysis yielded ceanothic acid, whose activity is specific to M. phlei at 100 mu g. M. phlei causes chronic ambulatory peritoneal dialysis-associated peritonitis.