Toosendanin relatives, trypanocidal principles from Meliae Cortex.

Area of Science:

• Pharmacology
• Natural Products Chemistry
• Medicinal Chemistry

Background:

• African Trypanosomiasis poses a significant global health challenge.
• Limited therapeutic options necessitate the discovery of new trypanocidal agents.
• Medicinal plants are a valuable source for novel drug discovery.

Purpose of the Study:

• To identify and isolate trypanocidal compounds from Meliae Cortex.
• To evaluate the activity and selectivity of isolated compounds and their derivatives.
• To elucidate structure-activity relationships for enhanced trypanocidal efficacy.

Main Methods:

• Screening of ~300 methanolic plant extracts.
• Bioassay-guided fractionation using liquid-liquid partition and chromatography (silica gel, ODS).
• Chemical synthesis of toosendanin derivatives and bioactivity evaluation.

Main Results:

• Meliae Cortex MeOH extract demonstrated potent trypanocidal activity.
• Toosendanin (1) and related compounds were isolated as active principles.
• Toosendanin exhibited potent trypanocidal activity and a high selective index.
• The epoxide moiety was crucial for activity; 3-O-acetyl and 7-hydroxyl groups were important.
• Methylpropionyl group addition enhanced trypanocidal activity.

Conclusions:

• Toosendanin is the primary active trypanocidal principle in Meliae Cortex.
• Structure-activity relationship studies identified key functional groups for potent activity.
• Derivatives of toosendanin show potential as novel therapeutic agents for African Trypanosomiasis.