Entomopathogenic fungi are fungal parasites of insects. During their
infection to insects, they are known to evade insect immunities and
kill the host insects by secreting several bioactive substances.1–3 As the
high productivity has been well established by continuous discovery of
novel bioactive compounds,4–6 entomopathogenic fungi have been
regarded as a source of bioactive compounds. Especially, those
belonging to the genus Lecanicillium (formerly Verticillium lecanii)
can be good source of novel compounds, as exemplified by the
isolation of indolosesquiterpenes (lecanindoles A–D7), phenopicolinic
acid derivatives (vertilecanins8) and pregnanes.9,10
Here we would like to report isolation and structure determination
of two compounds, verlamelin (verlamelin A, 1) and it new derivative
(verlamelin B, 2) from entomopathogenic fungus Lecanicillium sp.
Although the planar structure of verlamelin has already been
reported, its structure determination was only preliminary, because
these reports lacked detailed information on the signal assignments of
1H/13C, the signal connectivity in HSQC/HMBC and the D/L
configuration of the component amino acids.11–13 Furthermore, the
configuration of a hydroxyl group on the 5-hydroxytetradecanoic acid
moiety has not yet been determined. Therefore, in order to
completely establish the structure of verlamelin, we conducted a
detailed structure determination of 1 and 2
Entomopathogenic fungi are fungal parasites of insects. During theirinfection to insects, they are known to evade insect immunities andkill the host insects by secreting several bioactive substances.1–3 As thehigh productivity has been well established by continuous discovery ofnovel bioactive compounds,4–6 entomopathogenic fungi have beenregarded as a source of bioactive compounds. Especially, thosebelonging to the genus Lecanicillium (formerly Verticillium lecanii)can be good source of novel compounds, as exemplified by theisolation of indolosesquiterpenes (lecanindoles A–D7), phenopicolinicacid derivatives (vertilecanins8) and pregnanes.9,10Here we would like to report isolation and structure determinationof two compounds, verlamelin (verlamelin A, 1) and it new derivative(verlamelin B, 2) from entomopathogenic fungus Lecanicillium sp.Although the planar structure of verlamelin has already beenreported, its structure determination was only preliminary, becausethese reports lacked detailed information on the signal assignments of1H/13C, the signal connectivity in HSQC/HMBC and the D/Lconfiguration of the component amino acids.11–13 Furthermore, theconfiguration of a hydroxyl group on the 5-hydroxytetradecanoic acidmoiety has not yet been determined. Therefore, in order tocompletely establish the structure of verlamelin, we conducted adetailed structure determination of 1 and 2
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