RESUMO
To study the chemical constituents of the fruits of Fructus carotae, silica gel column chromatography and preparative HPLC were used to isolate and purify the extract of Fructus carotae. The structures of obtained compounds were elucidated on the basis of physicochemical property and spectral data. Nine guaiane-type sesquiterpenes were isolated and identified as 8β-angeloyloxy-11-hydroxy-4-guaien-3-one(1), 11-acetoxy-4-guaien-3-one(2), 11-acetoxy-8β-isobutyryl-4-guaien-3-one(3), 11-acetoxy-8β-propionyl-4-guaien-3-one(4), 11-hydroxy-4-guaien-3-one(5), 11-acetoxy-8β-angeloyloxy-1β-hydroxy-4-guaien-3-one(6), 11-acetoxy-8β-angeloyloxy-4-guaien-3-one(7), 11-acetoxy-8β-hydroxy-4-guaien-3-one(8)and 8β,11-dihydroxy-4-guaien-3-one(9). Compound 1 is a new compound, compound 5 is a new natural product, and compounds 2-4 were isolated from this genus for the first time.
RESUMO
OBJECTIVE: To modify the structure of Ursolic acid(UA), a pentacyclic triterpene acid, existing a variety of natural plants with extensive biological activities thus to increase the diversity of structure of UA and lay the foundation for screening more active compounds. METHODS: The structure of UA was modified by Streptomyces griseus subsp. griseus CGMCC 4.18 by microbial transformation. RESULTS: A rare hydroxylated at 2 position, product corosolic acid, 2α, 3β-dihydroxy-urs-12-en-28-oic acid which is difficult to obtain by chemical methods and the product 3, 4-seco-ursan-4-hydroxy-12-en-3, 28-dioic acid with cleavage of ring-A were yielded. Interesting, the hydroxylation at C-2 is α configuration that is rare. The structures of product were established based on spectroscopic data and reference compounds. CONCLUSION: The structure diversity of ursolic acid was increased by microbial transformation by Streptomyces. Furteremore, microbial transformation illustrated regional selectivity and high stereo-selectivity.
