Studies on the Microbial Transformation of Steroidal Sappogenins: Sarsasapogenin,Dihydrosarsasapogenin,and Kryptogenin

• Main Authors: Lin,Kung-Yin, 林恭印
• Other Authors: Lee,Shuei-Sheng;Wang,Kuang-Chao
• Format: Others
• Language: zh-TW
• Published: 1995
• Online Access: http://ndltd.ncl.edu.tw/handle/43620759026750046840

碩士 === 國立臺灣大學 === 藥學研究所 === 84 === The Mycobacterium sp.(NRRL B-3805) is known for its capability to cleave the 17-alkyl side chain of several sterols such as choles- terol,sitosterol,stigmasterol,and campesterol with formation of 17-keto steroids.In order to find out that whether this microorg- anism is capable of cleaving the sapogenin-type side chain,sarsa- sapogenin,dihydrosarsasapogenin and kryptogenin were incubated with this microorganism.When incubated with Mycobacterium sp.(NR- RL B-3805),the sarsasapogenin kept the spirostane structure inta- ct as expected,the only change is oxidation of the 3β-hydroxyl group to carbonyl and introduction of a Δ4 double bond.This sa- rsasapog-4-en-3-one is the major product and isolated in 62% yie- ld.Dihydrosarsasapogenin was obtained from sarsasapogenin by rea- cting with lithium aluminum hydride and aluminum chloride. After incubation, we obtained 6 products (compounds 4-9).Compounds 4-6 were formed by the cleavage of the bond between C-23 and C-25, then the C-24 acid were methylated to form methyl ester.The most special is that the A,B rings of 5 and 6 are trans-juction inst- ead of cis-juction.It could not be explained by the known mecha- nism.Compound 8 and 9 were formed by breaking the bonding of C-22 and C-23,and were the same as the microbial transformation prod- ucts of lanosterol derivatives.Compound 7 was the only 19 carbons steroid,but the same as 8 and 9,having a hydroxyl group at C-12. Kryptogenin is devoid of rings E and F,the ring system in the sp- irostane, and has keto functions at C-16 and C-22.We obtained 4 products (compounds 11-14) after the incubation of kryptogenin with Mycobacterium sp.(NRRL B-3805).Compound 11 is the same as kryptogenin except the formation of 4-en-3-one.Compound 12 was obtained by the cleavage of the bond between C-24 and C-25,and formed C-24 alcohol.13 and 14 was supposed that the bond between C-25 and C-26 was broken and formed C-25 alcohol or C-25 ketone.