Evaluation of in vitro Antibacterial and Sun Protective Activities of Methanolic Extract of Phoenix dactylifera Seeds and Formulation of an Herbal Sunscreen Cream.

Abstract

Background: Phoenix dactylifera, a fruit-harvesting nutrient and therapeutic plant, has been used in drug development and traditional medicine due to its rich nutritional content. Objective: To evaluate the in vitro antioxidant, antibacterial, sun screening, and phytochemical properties of Phoenix dactylifera seeds of fruits purchased from the local market in Sri Lanka and formulate an herbal cream incorporating this extract, assessing its physical, sun protection factor (SPF), and antibacterial properties and stability Methods: The extract was obtained using ultrasonic-assisted methanolic extraction method and analyzed for presence of phytochemicals, antioxidant activity (DPPH assay), antibacterial activity against S. aureus and SPF. The required concentration of extract was determined to give an SPF of over 30. Formulations F1 (5%) and F2 (1%) with different proportions of crude were prepared and analyzed for physical stability and SPF over 7 days at room temperature (30±2 ºC). The antibacterial activities of formulations were determined. Results: Phytochemical screening revealed the presence of several compounds and the extract had low antioxidant activity with an IC50 of 24.70±0.08 µg/mL, while ascorbic acid (the positive control) had an IC50 of 6.34±0.02 µg/mL. The extract's antibacterial activity produced zones of inhibition (ZOIs) larger than 11 mm at the concentrations of 50, 75, and 150 mg/mL, compared to ciprofloxacin 3 mg/mL (positive control) with a ZOI of 29.43±0.46 mm. The extract showed SPF greater than 30 at 6.0 mg/mL. Over 7 days, both creams remained stable in pH, odor, color, and homogeneity with tolerable changes in SPF. The SPF values of freshly prepared solutions (10 mg/mL) of F1 and F2 were 36.22±0.02 and 33.91±0.03, respectively and on the 7th day, they were 36.96±0.03, 34.57±0.03, respectively. F1 showed moderate antibacterial activity at 50 mg/mL concentration (ZOI = 11.74±0.05 mm). Conclusions: Phoenix dactylifera seed extract demonstrates antioxidant, antibacterial and sun screening properties. The cream formulations showed promising stability and efficacy, highlighting their potential as natural sun protection products.