The Chemical and Antibacterial Evaluation of St. John's Wort Oil Macerates Used in Kosovar Traditional Medicine

Abstract

Hypericum perforatum L. (Hypericaceae), or St. John's Wort, is a well-known medicinal herb often associated with the treatment of anxiety and depression. Additionally, an oil macerate (Oleum Hyperici) of its flowering aerial parts is widely used in traditional medicine across the Balkans as a topical wound and ulcer salve. Other studies have shown that Oleum Hyperici reduces both wound size and healing time. Of its active constituents, the naphthodianthrone hypericin and phloroglucinol hyperforin are effective antibacterial compounds against various Gram-positive bacteria. However, hyperforin is unstable with light and heat, and thus should not be present in the light-aged oil macerate. Additionally, hypericin can cause phototoxic skin reactions if ingested or absorbed into the skin. Therefore, the established chemistry presents a paradox for this H. perforatum oil macerate: the hyperforin responsible for the antibacterial bioactivity should degrade in the sunlight as the traditional oil is prepared; alternately, if hypericin is present in established bioactive levels, then the oil macerate should cause photosensitivity, yet none is reported. In this research, various extracts of H. perforatum were compared to traditional oil macerates with regards to chemical composition and antibacterial activity (inhibition of growth, biofilm formation, and quorum sensing) vs. several strains of Staphylococcus aureus in order to better understand this traditional medicine. It was found that four Kosovar-crafted oil macerates were effective at inhibiting biofilm formation (MBIC50 active range of 0.004–0.016% v/v), exhibited moderate inhibition of quorum sensing (QSIC50 active range of 0.064–0.512% v/v), and contained detectable amounts of hyperforin, but not hypericin. Overall, levels of hypericin were much higher in the organic extracts, and these also exhibited more potent growth inhibitory activity. In conclusion, these data confirm that oil macerates employed in traditional treatments of skin infection lack the compound credited with phototoxic reactions in H. perforatum use and exhibit anti-biofilm and modest quorum quenching effects, rather than growth inhibitory properties against S. aureus.

The Influence of Carrier Oils on the Antimicrobial Activity and Cytotoxicity of Essential Oils

“…The antimicrobial activity of the carrier oil, however, is reported for the first time in this study. As with this study, P. armeniaca has also previously been reported to display poor antimicrobial activity (>2.00% v/v) against E. coli , P. aeruginosa , S. aureus, and H. perforatum was previously shown to display poor to no antimicrobial activity against S. aureus [15]. However, to the best of our knowledge, the antimicrobial activity of C. officinalis and P. americana carrier oils are reported here for the first time against all 11 pathogens.…”

“…The chemical composition of the essential oils has been previously reported [1] and is included in Table 1. It is known that the chemical composition of essential oils may vary due to differences in chemotype, storage, harvesting, or plant origin [13–15]. For example, the sample of Thymus vulgaris from this study has a lower content of thymol (18.9%) than reported in previous studies (44.7-48.9%) [16–18] and the Laurus nobilis sample used in this study contains myrcene and chavicol, as opposed to high levels of 1,8-cineole (35.5-42.3%) as previously reported [19, 20].…”

Wound Healing with Botanicals: a Review and Future Perspectives

“…Furthermore, UVactivated hypericin exhibits necrotic and apoptotic effects on human keratinocytes and melanocytes [63]. Notably, chemical analysis of the traditional oleum hyperici formulation used throughout the Balkans as a topical therapy revealed the absence of hypericin in the resulting product; this aligned with ethnographic data suggesting frequent users of the oil did not exhibit symptoms of hypericism [54]. …”

“…A study on the antibacterial activity of H. perforatum extracts was found to differ substantially based on the extraction method used, with aqueous and organic extracts generally exhibiting more classic antibacterial activity in growth inhibition of pathogens, whereas the oleum hyperici formulation exhibited mild quorum quenching and anti-biofilm properties against Staphylococcus aureus [54]. A study on the efficacy of oleum hyperici on palatal wound healing in rabbits found that the topical oil treatment showed no additional benefit to healing over that of the control (the olive oil base) [55].…”

Traditional Asian Herbs in Skin Whitening: The Current Development and Limitations

“…First, most natural ingredients are difficult to extract and purify on a large scale ( Bai et al., 2014 ), and extraction costs are a key factor limiting the conversion of ingredients into products. Second, many herbal ingredients only show moderate effects and are unstable under normal conditions, their performance depends on the structure and properties ( Manda et al., 2014 ; Ho et al., 2016 ; Lyles et al., 2017 ). Thus, the molecular structure of some ingredients will be further improved before use, research in this area is under development.…”