RESUMO
This is the first report of a phytochemical investigation of Jamaican populations of a local folk medicinal plant Salvia coccinea (Lamiaceae/Labiatae). Apart from the presence of 3-sitosterol, phytochemical profiling of the aerial parts yielded compounds other than those previously reported from Indian and Italian populations. The triterpenes betulinic acid and betulin, the phytosterols beta-sitosterol and beta-sitosterol-3-O-beta-D-glucopyranoside, as well as the steroid precursor squalene were isolated. The structures of the compounds were established by comparison of NMR spectroscopic data with those reported in literature.
Assuntos
Salvia/química , Jamaica , Fitosteróis/química , Triterpenos/químicaRESUMO
Solvolytic rearrangement of the C/D ring system of the tetracyclic diterpenoid stemodinone (2) afforded the compounds 15(13-->12)abeo-13beta-hydroxystemaran-2-one (5) and 15(8-->9)abeo-8beta(H)-12beta-hydroxystachan-2-one (10). Terpene 5 possesses a novel diterpene skeleton. Oxidation of these compounds yielded their respective diketones. Bioconversion of 5 by Rhizopus oryzae yielded 15(13-->12)abeo-7beta,13beta-dihydroxystemaran-2-one (18) while microbial transformation of 10 provided 15(8-->9)abeo-8beta(H)-6alpha,12beta-dihydroxystachan-2-one (19), 15(8-->9)abeo-8beta(H)-7beta,12beta-dihydroxystachan-2-one (20) and 15(8-->9)abeo-8beta(H)-6alpha,12beta,14beta-trihydroxystachan-2-one (21). A rationale for the formation of the rearranged compounds is proposed.
Assuntos
Diterpenos/química , Diterpenos/metabolismo , Rhizopus/metabolismo , Scrophulariaceae/química , Biotransformação , Estrutura MolecularRESUMO
Incubation of 2alpha,13(R)-dihydroxystemodane (3) with Rhizopus oryzae ATCC 11145 gave 2alpha,7beta,13(R)-trihydroxystemodane (11) while biotransformation of 13(R)-hydroxystemodan-2-one (5) yielded 6alpha,13(R)-dihydroxystemodan-2-one (12) and 7beta,13(R)-dihydroxystemodan-2-one (13). Bioconversion of 2beta,13(R)-dihydroxystemodane (7) with Rhizopus afforded 2beta,7,13(R)-trihydroxystemodane (14). The results complement data from our previous work and provide more information about the effect of functional groups of stemodane substrates on the site of hydroxylation.
Assuntos
Diterpenos/química , Diterpenos/metabolismo , Oxigênio/química , Rhizopus/metabolismo , Biotransformação , Catálise , Diterpenos/isolamento & purificação , Hidroxilação , Estrutura Molecular , EstereoisomerismoRESUMO
A new stemodinoside, stemodin-alpha-L-arabinofuranoside (5), was isolated from the plant Stemodia maritima. Incubation of stemodin (2) with Rhizopus oryzae ATCC 11145 gave 2 alpha,7 beta,13(S)-trihydroxystemodane (17) and 2 alpha,3 beta,13(S),16 alpha-tetrahydroxystemodane (18) whilst stemodinone (8) afforded 6 alpha,13(S)-dihydroxystemodan-2-one (19). The bioconversion of 2 beta,13(S)-dihydroxystemodane (10) by the fungus yielded 2 beta,7 beta,13(S)-trihydroxystemodane (20) whereas stemod-12-en-2-one (9) provided 7 beta,17-dihydroxystemod-12-en-2-one (21). The results provide useful information about the relationship between the functional groups of the substrates and their potential for bioconversion.