Abstract
Quantification of biologically active marker compounds in crude drugs facilitates the production of therapeutically effective herbal formulations. The present study is designed to produce maiden work on quantification of a rare alkaloid solanopubamine in leaves and fruits of six different species of genus
Solanum
(
S. schimperianum
,
S. villosum, S. coagulans, S. glabratum, S. incanum and S. nigrum
extracted by two different methods) by a validated high performance thin layer chromatography method. Chromatography was performed on glass-backed silica gel 60 F254 precoated HPTLC plates with solvents CHCl
3
: CH
3
OH: NH
4
OH (30:20:1.5
v
/
v
) as the mobile phase. After development, the HPTLC plate was derivatized with dragendorff reagent, scanned, and quantified at 500nm. The system was found to give compact spot for solanopubamine at
R
f
= 0.39 ± 0.01. The linear regression analyses data for the calibration plot showed good linear relationship with r
2
= 0.998 with respect to area in the concentration range of 100 – 900 ng. The regression equation for standard solanopubamine was found to be Y =-239.618 + 4.442x. The steroidal alkaloid solanopubamine was found to be present only in leaves extracts of
S. schimperianum
while it was absent in fruit extract of
S. schimperianum
and leaves as well as fruit extracts of
S. villosum, S. coagulans, S. glabratum, S. incanum
and
S. nigrum
. The LOD and LOQ were found to be 35 ng and 110 ng band-1, respectively. The quantity of solanopubamine in leaves extract of
S. schimperianum
extracted by ethanol only and mixture of ethanol and ammonium hydroxide (6:4) was found to be 1.03% w/w and 2.09% w/w, respectively. Stress studies of solanopubamine exhibited the maximum (100%) degradation in base and H
2
O
2
treated samples and 61.4% in acid treated samples. The UV exposure and photo-oxidation to sample almost caused no damage but 12.91%, 13.83% and 14.08% destruction has been observed while exposed to room temperature, 40 deg. C and 50 deg. C, respectively.