Our studies on the constituents of so far above forty species of Solanum genera plants have resulted in the isolation of steroidal glycosides potent cytotoxity, antifeedant, anti HSV-
1
activities and of the key intermediate on the biosynthesis of solasodine. On the way of these Solanum plants investigation, unusual peculiar steroidal saponins with opened
E
-ring type,
AF
-1024, which corresponds to the precursor of the spirostanol and furostanol, 16,
22
-dicarbonyl type steroids,
AF
-a-
1
and -2, and a 20-
22
-seco-type steroid, SNI-14, have been obtained together with many usual furostanol and spirostanol type glycosides from some Solanum genera, three formers of which were from the fruits of Solanum anguivi, and the latter from the aerial parts of Solanum nigrum, respectively. The structure of
AF
-1024 was characterized as 3-O-chacotriosyl 3,16,
22
,26-tetrahydroxycholest-
5
-ene 26-O- -D-glucopyranoside. The configurations at
C
-16 and -
22
were not defined, however, this compound is regarded as an important precursor which would produce furostanol and spirostanol showing a variety of bio-activities.
AF
-a-
1
and -2 were assumed to be isomers at
C
-23. The structure of
AF
-a-
1
was characterized as 3-O- -chacotriosyl (23S,26)-23,26-epoxy-3,26-dihydroxycholest-
5
-ene-16,
22
-dione. On alkaline treatment, both afforded the identical product. This compound was shown to be 3-O- -chacotriosyl 20-caboxypregna-
5
-ene 16-one. The occurrence of
AF
-a-
1
and -2 are regarded as genuine constituents probably produced directly from
AF
-1024 on the biogenetic route. The structure of SNI-14 was characterized as 3-O- -lycotetraosyl 3,16,20(S)-trihydroxy-
5
-pregnane 16-O-(
5
-O- -D-glucopyranosyl-4(S)-methyl-
5
-hydroxypentanoic acid)-ester. This compound was supposed that it would be produced via furostanol glycoside as if Marker degradation took place in plant body. Representative these unusual novel compounds obtained in this time would provide additional important new pathways, route-A and route-
B
, for steroidal biogenesis.
抄録全体を表示