A comparative analysis of leaf essential oil profile, in vitro biological properties and in silico studies of four Indian Guava (Psidium guajava L.) cultivars, a promising source of functional food

Essential oils extracted from Psidium guajava L. (Guava) are considered effective with a wide range of bioactivities. However, there is only a little scientific evidence for comparative studies on Indian Guava cultivars. The present research is aimed to determine the variation in chemical composition and biological efficiencies of essential oils extracted from the cultivars, Surka chitti, Allahabad safeda, Karela, and Lucknow-49. Essential oil from the leaves was extracted by hydro-distillation and chemical characterization was performed through GC–MS/GC-FID. The essential oils were screened for in vitro biological assays like antidiabetic, tyrosinase inhibitory, anti-inflammatory, antibacterial, and antioxidant activities. Totally 64 chemical constituents were isolated from guava cultivars with (E)-β-ocimene (more than 40% in all cultivars), (E)-caryophyllene and epiglobulol (11.3% in Lucknow-49), caryophyllene oxide (9.7% in Allahabad safeda), epi‑α-muurolol (9.3% in Surka chitti), globulol (7.3% in Surka chitti), and muurola-4,10(14)‑dien-1-β-ol (4.7% in Surka chitti) as notable compounds. Lucknow-49 cultivar showed a good enzyme inhibition effect against the enzymes α-amylase (IC50 of 220.93±0.81 µg/mL) and α-glucosidase (221.02±0.38 µg/mL). Karela cultivar expressed a potent tyrosinase inhibition effect (133.45±0.97 µg/mL) and Lucknow-49 exhibited strong anti-inflammatory activity (41.04±1.06 µg/mL) compared to the standard diclofenac (128.03±0.6 µg/mL). Likewise, Surka chitti (223.95±0.25 µg/mL in ABTS and 177.06±0.53 µg/mL in DPPH assays) and Lucknow-49 (236.51±0.55 µg/mL) showed notable antioxidant activity. Computational docking study suggests that the major compounds of guava cultivars potentially lead to enzyme inhibition with good docking scores. This binding interaction might be due to their HH and π-H interaction. The report highlights the variation in pharmacological properties and is helpful for identification of elite guava cultivars to boost the commercial potential of this crop as valuable bioactive extracts.