Chemical profile, antiproliferative, antioxidant and enzyme inhibition activities of Ocimum basilicum L. and Pulicaria undulata (L.) C.A. Mey. grown in Sudan

In the present study, essential oils extracted from the leafy stems of Ocimum basilicum (Family Lamiaceae) and Pulicaria undulata (Family Asteraceae) were investigated for their chemical profiles and biological activity including antioxidant, antiproliferative and enzyme inhibition activities. The chemical composition of essential oil was determined using Gas Chromatography-Mass Spectrometry. The antioxidant capacity was tested by scavenging of free radicals, reduction potential, chelating ability on ferrous ions and phosphomolybdenum assays. Cell viability was evaluated on human breast carcinoma (MCF7) and human colon adenocarcinoma (HT29 and HCT116) cell lines. Enzymatic activity was evaluated against α-glucosidase, α-amylase, acetylcholinesterase, butyrylcholinesterase, and tyrosinase. Based on the results obtained, in silico studies was performed to identify potential inhibitor of tyrosinase activity. Results showed that oil of O. basilicum was predominantly composed of methyl chavicol (51.9%) followed by linalool (20.0%). Oil of P. undulata was represented by oxygenated monoterpenes (96.9%) with carvotanacetone (92.1%) as the main molecule. Both oils exerted antioxidant activities with oil from P. undulata exerted significant (p<0.05) higher scavenging activity (20.92±0.05DPPH and 62.36±0.25ABTS mg trolox equivalents (TEs)/g) while that obtained from O. basillicum showed significant (p<0.05) higher total antioxidant activity (16.72±0.95 mmol TEs/g), ion reducing power (86.30±2.80FRAP and 115.31±2.03CUPRAC mg TEs/g) and metal chelating ability (21.08±3.45 mg disodium edetate equivalents /g). Both oils showed considerable tyrosinase and α-amylase inhibition activity while only oil of P. undulata displayed acetylcholinesterase (0.95 ± 0.06 mg galanthamine equivalents (GALAEs)/g), butyrylcholinesterase (1.19 ± 0.13 mg GALAEs/g) and α-glucosidase (32.59 ± 0.20 mg acarbose equivalents (ACAEs)/g) inhibition capacity. Both oils showed good anti-proliferative activity towards the three cell lines with higher activity observed from that of O. basillicum (2.8–3.3 µg/mL). In silico studies suggested that methyl chavicol represent a potential inhibitor of tyrosinase activity. In conclusion, the two oils show promise as natural agents with functional properties for food, cosmetics, and pharmaceutical industries.