Antioxidant, Antimicrobial and Formulation of Borage (Borago officinalis) Seeds Oil and Leaves Extracts as Microemulsion

Aims: This study aims to investigate antioxidant and antibacterial activities of borage (seeds and leaves) extracts, and to prepare different topical microemulsion formulations using borage oil.

Study Design: Borage seeds and leaves were collected from Hebron -Palestine, then the borage leaves and seeds were prepared for extraction and then extracted with Soxhlet using ethanol. The antimicrobial and antioxidant activity of the extracts were studied, and then Ternary Phase Diagram was constructed using the borage extracts (from seeds and leaves).

Methodology: The seeds were cultivated upon their ripening season in April of 2016 from the Halhul mountains in Hebron/Palestine. Soxhlet method was used to extract borage seeds and leaves oil by using ethanol 95%. A ternary phase diagram was constructed by determining appropriate nonionic surfactant to assess the ability for microemulsion formulation and durability of each system. Tween 80 was found to be more suitable to solubilize each of borage seeds and leaves extracts compared with Tween 20 due to its prominent hydrophobic properties. The antibacterial activity was evaluated for both borage seeds and leaves extracts using a well diffusion method against Staphyloococcus aureus, Escherichia coli, &Candida albicans.

Results: Results showed that the seeds extract has inhibition zone (12 mm) against S. aureus (gram positive bacteria) higher than inhibition zone that leaves extracts exhibited (7.5mm), but no significant effects observed for both extracts against E. coli and C. albicans. In addition, antibacterial activity for microemulsions formulation was measured against S. aureus, E. coli, and C. albicans. Results showed that there is minor activity against S. aureus when compared to PenicillinG and the pure seed oil or leaves extract. In contrast no activity was reported against E. coli and C. albicans. The antioxidant activity was further indicated by the quiet good ability to reduce the FRAP reagent for both extracts with the indication of higher seeds extract activity. This variation is explained by the higher seeds extract content of polyphenol, tocopherol and vitamin C than leaves extract.

Conclusion: Borage seeds and leaves were extracted, and the extracts were showed antimicrobial and antioxidant activity and showed that they can be used in microemulsion using ternary phase diagram.