H.W.L.S. GUNARATHNA¹, R.M. DHARMADASA^2,, I.J. AMADORU¹, D.C. ABEYSINGHE¹

Essential oil extracted from mandarin (Citrus reticulata Blanco.) (Rutaceae) is widely used in traditional medicine, pharmaceutical, food and cosmetic industries. However, the use of citrus leaf oil is not well established, and information is lacking. This study aimed to quantify the yield of essential oil content and evaluate the functional properties of essential oil extracted from immature and mature leaves of five different mandarin varieties (Indu, Heennaran, Madhu, Juicy and Rahangala) grown in Sri Lanka. The essential oil was distilled using Clevenger-type apparatus. Quantification of total phenolic content (TPC), total flavonoid content (TFC) and total antioxidant capacity (TAC) were carried out by using the modified Floin-Ciocalteu method, colourimetric method and ferric reducing antioxidant power (FRAP) assay, respectively. The results revealed that all tested leaf essential oil of mandarin varieties contained marked amounts of essential oil content and TPC, TFC, and TAC. Significantly highest TPC (69.80 ± 5.14 mg GAE/g DW), TFC (265.08 ± 7.95 mg RE/ g DW), TAC (87.70 ± 4.02 mg TE/ g DW) and essential oil content (1.89 ± 0.19 mL/ 100 g DW) were observed in the Indu mandarin variety. Moreover, there were positive correlations of TAC with TPC (R² = 0.8822) and TFC (R² = 0.4004). The greater availability of bioactive compounds in C. reticulata leaf essential oil highlighted that the essential oil of mandarin is a potential source of valuable components. This research highlights the promising potential of utilizing the leaf essential oil of C. reticulata as a rich source of these beneficial components in the pharmaceutical, food and cosmetic industries.

Areal plant parts, Citrus reticulata, Essential oil, Functional properties, Mandarin