Antifungal alkaloids from the fresh rattan stem of Fibraurea recisa Pierre.

ABSTRACT

AIM OF THE STUDY The rattan stem of Fibraurea recisa Pierre. is known as an ethno-remedy commonly used for the treatment of various skin diseases by the minority Yao, Zhuang and Miao in Yunnan Province of China. The present study was designated to evaluate its antifungal activity, and to root out the antifungal substances from this ethical herb. MATERIALS AND METHODS: The in vitro antifungal assay was performed by agar diffusion test for extracts and fractions. Then, the active fractions were submitted to column chromatography on silica gel and LH-20 to isolate their compounds. And the antifungal activity of pure compounds has been examined by checkerboard microdilution test. Nine Candida strains and one Cryptococcus strain were used for the bioassay. RESULTS: The MeOH extract exhibited significant antifungal activity, and the alkaloidal fractions were deduced as main active component. Subsequent studies led to the identification of a new alkaloid fibrecisine (1) and 21 known alkaloids including berberines, tetrahydroberberines and aporphine derivatives. The bioassay result indicated that the berberines showed more potent activity than aporphine derivatives against the test Candida strains, while tetrahydroberberines showed very weak activity against Cryptococcus neoformans. CONCLUSION: The new alkaloid fibrecisine (1) was identified as 1,2-methylenedioxy-8-hydroxy-6a(R)-aporphine by detailed spectral analysis. The rattan stem of Fibraurea recisa Pierre. is an effective antifungal herb, and its major active component is alkaloidal compounds. Bioassay tests revealed that the water-soluble berberines are the most important antifungal substances. The study provides preliminary scientific validation for the traditional medicinal use of this ethno-remedy.