Spectral characterization, analgesic, and anti-inflammatory effects of ethanolic extract of Calotropis procera leaf and dry latex from Jazan, Kingdom of Saudi Arabia

Traditional healers have used the shrub Calotropis procera (CP) for many years for various therapies. The present study investigated the bioactive constituents of ethanolic extract of CP leaf and dried latex using gas chromatography-mass spectrometry and Fourier transforms infrared spectroscopy. The identification and characterization of the compounds were confirmed by examining the constituents' mass spectrum fragmentations and FT-IR spectra and comparing the results with those in the literature. The tail-flick method was used to investigate the analgesic properties of the extract and its anti-inflammatory activities using a rat model of formalin-induced oedema. Acute oral toxicity in rats was studied per OECD recommendations. Twenty male rats were divided into four groups and received an ethanolic extract of the leaves and dried milky sap of CP (200 mg/Kg) in groups 1, 2, and 3. Group 4 rats were administered aspirin 50 mg/kg as a positive control. The CP dried latex extract has the highest content of lupeol and its acetate derivative compared to its leaf extract. The CP dried latex extract inhibited inflammation more significantly than the ethanolic leaf extract and the drug indomethacin at a higher dosage (200 mg/kg). The ethanolic extracts showed analgesia comparable to aspirin. It suggests that fatty acids and their esters, particularly ethyl linoleate (8.96%), ethyl palmitate (7.99%), ethyl linoleate (6.98%), and palmitic acid (5.18%), may be valuable biomarkers for characterizing leaf and latex samples and describing the medicinal potential of CP.