<span style="font-size: 21.5pt;mso-bidi-font-size:14.5pt;font-family:"Times New Roman","serif"">Isolation, purification and partial chemical characterization of a lethal factor from common Indian toad <i>(Bulo melanostictus, </i>Schneider) skin extract </span>

Abstract

<span style="font-size: 15.5pt;mso-bidi-font-size:8.5pt;font-family:" times="" new="" roman","serif""="">Indian toad <i><span style="font-size:16.0pt;mso-bidi-font-size:9.0pt; font-family:" times="" new="" roman","serif""="">(Bufo melanosticus, </span></i><span style="font-size:15.5pt;mso-bidi-font-size:8.5pt;font-family:" times="" new="" roman","serif""="">Schneider) skin extract (TSE) is pharmacologically potent and probably contains several bioactive compounds [Das <i><span style="font-size:16.0pt;mso-bidi-font-size:9.0pt; font-family:" times="" new="" roman","serif""="">et. al., Indian </span></i><i><span style="font-size:15.0pt;mso-bidi-font-size:8.0pt;font-family:" arial","sans-serif""="">J </span></i><i><span style="font-size:16.0pt;mso-bidi-font-size:9.0pt; font-family:" times="" new="" roman","serif""="">Pharmacal, </span></i><span style="font-size:15.5pt;mso-bidi-font-size:8.5pt;font-family:" times="" new="" roman","serif""="">28 (1996) 72). A lethal factor was isolated and purified by neutral alumina column chromatography followed by HPLC. Spectroscopic (UV, IR, FAB-MASS) study indicated that the lethal factor (TSE-LF) was a 254 Da long chain compound with carbonyl, hydroxyl and ester as functional groups. LD₅₀ of

<span style="font-size: 15.5pt;mso-bidi-font-size:8.5pt;font-family:" times="" new="" roman","serif""="">TSE-LF was found to <span style="font-size:15.5pt;mso-bidi-font-size:8.5pt; font-family:" arial","sans-serif""="">be <span style="font-size:15.5pt; mso-bidi-font-size:8.5pt;font-family:" times="" new="" roman","serif""="">3.5 mg/kg (iv). Biological study showed that TSE-LF possesses hypotensive, cardiotoxic, neurotoxic activity and produced death by apnoea in experimental animal. Cyproheptadine antagonised TSE-LF induced contraction of isolated smooth muscle indicating involvement of histamine/serotonin receptors. TSE-LF induced neurotoxic action on chick biventer cervices was mediated through Ca²^{<span style="font-size:13.5pt;mso-bidi-font-size:6.5pt;font-family:" arial","sans-serif""="">+</span>}<span style="font-size:13.5pt;mso-bidi-font-size:6.5pt;font-family:" arial","sans-serif""=""> <span style="font-size:15.5pt;mso-bidi-font-size:8.5pt;font-family:" times="" new="" roman","serif""="">ion.

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