Abstract

Background: C. delpyi, C. decalvatus and C. caudatus are in the Euphorbiaceae family. The aerial parts, such as twigs, leaves and barks of these plants are used as traditional medicine such as anti-inflammatory, cytotoxicity, and antifungal properties.

Objectives: The aims of this work were 1) to study the chemical composition of C. delpyi, C. decalvatus, and C. caudatus 2) to test the antibacterial, anti-HIV-1 RT, and cytotoxicity activities of crude extracts and pure compounds from these plants.

Methods: Extraction, separation and purification of three plants were performed following chromatographic method. The biological activities, including antibacterial, anti-HIV-1 RT and cytotoxicity assay of three plants, were evaluated by the standard methods.

Results: Phytochemical investigation of C. delpyi highlighted a new clerodane diterpenoid; crotondelpyitin A (1). The five known compounds were found, such as acetyl aleuritolic acid (2), 5- hydroxy-7,4′-dimethoxyflavone (3), and pilloin (4) in C. decalvatus and 3α-benzoyloxy-D while Afriedo- oleanan-27,16α-lactone (5), and bergenin (6) in C. caudatus. Compound 3 showed the most effective antibacterial activities with MIC in range <0.16 -1.25 mg/mL, and MBC in range 0.6 - >5.0 mg/mL. The six compounds were inactive with anti-HIV-1 RT. In addition, compound 4 was active for cytotoxic activities on FaDu and KKU-M213 at <4 μg/mL.

Conclusion: The present study reveals that the Croton species are sources of diterpenoid-type compounds and a significant guide for further research of chemical constituents from these plants as potential medicines.

Keywords: Croton delpyi, croton decalvatus, croton caudatus, clerodane diterpenoid, HIV-1, phytochemical.

Graphical Abstract