Evaluation of anti-inflammatory potential and GC-MS profiling of leaf extracts from Clerodendrum infortunatum L

Abstract

Ethnopharmacological relevance: Clerodendrum infortunatum L. is commonly distributed in tropical and subtropical countries and is widely used in the indigenous systems of medicine including Ayurveda, Unani, and Homeopathy. The plant has important uses in the treatment of various inflammatory disorders which includes asthma, cough, chest complaints, pain, rheumatism, osteoarthritis, gastric ulcer, cancer, diabetes, skin diseases etc. AIM OF THE STUDY: Regarding the extensive healing properties of C. infortunatum in folk medicine, we aimed to explore the anti-inflammatory activity of the plant and analyze its bioactive components.

Materials and methods: Sequential extracts were prepared from C. infortunatum leaves using n-hexane, dichloromethane, ethyl acetate, methanol, ethanol and water. In vitro anti-inflammatory activity of these extracts were evaluated using membrane stabilization and protein anti-denaturation assays. Toxicity of the extracts was tested using brine shrimp lethality assay. GC-MS analysis has been carried out to analyze and characterize various bioactive constituents present in the plant.

Results: Each of the tested extracts showed significant (p < 0.05) in vitro anti-inflammatory activity. Sequential ethyl acetate extract demonstrated the strongest membrane stabilization and protein anti-denaturation activities with IC₅₀ values of 331.3, 308.3 and 279.2 μg/mL for heat and hypotonicity induced membrane stabilization and protein anti-denaturation assays, respectively. Sequential methanol extract also exhibited strong activity in heat and hypotonicity induced membrane stabilization and protein anti-denaturation assays with IC₅₀ values of 371.5, 331.6 and 284.6 μg/mL, respectively. The extracts demonstrated a range of toxicity in the brine shrimp lethality assay with LC₅₀ values of 51.4, 59.7, 47.3, 37.1, 68.1 and 77.3 μg/mL for n-hexane, dichloromethane, ethyl acetate, methanol, ethanol and water extracts respectively. The GC-MS analysis of direct n-hexane, ethyl acetate and methanol extracts detected 32 different compounds. The major compounds (> 5%) were phenol, 3,5-bis(1,1-dimethylethyl)-, hexadecanoic acid methyl ester, estragole, methyl stearate, lanosterol, 9-methoxybicyclo[6.1.0]nona-2,4,6-triene, benzenepropanoic acid, 3,5-bis(1,1-dimethylethyl) 4 hydroxy methyl ester, 22,23-dibromostigmasterol acetate, 3-methyl-4-(phenylthio)-2-prop-2-enyl-2,5-dihydrothiophene 1,1-dioxide, benzenemethanol, α-methyl-α-propyl- and 9-octadecenoic acid (Z)- methyl ester.

Conclusions: The findings of our study revealed that C. infortunatum is rich with diverse bioactive phytoconstituents and the scientific evidences support the anti-inflammatory potential of the plant.

Keywords: Bioactive constituents; Clerodendrum infortunatum; Cytotoxicity; Inflammation; Membrane stabilization; Protein anti-denaturation; Sequential extract.