An assessment of the growth inhibition profiles of Hamamelis virginiana L. extracts against Streptococcus and Staphylococcus spp.

Abstract

Staphylococcal and streptococcal species trigger a wide variety of infections involving epithelial tissues. Virginian witch hazel (WH; Hamamelis virginiana L.; family: Hamamelidaceae) is a plant that has been used traditionally by Native Americans to treat a variety of skin conditions. Extracts from the leaves were examined for their inhibitory effects on these bacterial species. Solvents of different polarity (water, methanol, ethyl acetate, hexane and chloroform) were used to prepare extracts from WH leaves, and the aqueous resuspensions were screened for antibacterial activities using disc diffusion and liquid dilution assays. Extract phytochemical profiles and toxicities were also examined, and combinations of extracts with conventional antibiotics were tested against each bacterial strain. The methanolic and aqueous extracts inhibited the growth of S. oralis , S. pyogenes , S. epidermidis and S. aureus , but not S. mutans . The extracts were especially active against staphylococcal species, with MIC values between 200 and 500 μg/ml. Combinations of active extracts with conventional antibiotics failed to yield beneficial interactions, except for two cases where additive interactions were observed (aqueous WH extract combined with chloramphenicol against S. oralis , and methanolic WH extract combined with ciprofloxacin against S. aureus ). Phytochemical assays indicated an abundance of tannins, triterpenoids and phenolics in the water and methanol extracts, with trace amounts of these components in the ethyl acetate extract. Phytochemicals were not detected in hexane and chloroform extracts. Thus, phytochemical abundance in extracts was concordant with antibacterial activities. All extracts were found to be non-toxic in Artemia nauplii assays. These findings indicate the potential for WH leaf extracts for clinical use in treating staphylococcal and streptococcal infections, while substantiating their traditional Native American uses.

Anti-Inflammatory and Anti-Acne Effects of Hamamelis virginiana Bark in Human Keratinocytes

“…Tannin-rich extracts from Hamamelis virginiana L. are traditionally used to treat various skin infections due to their putative antioxidant, anti-inflammatory, and antibacterial properties [ 18 , 22 ]. The release of IL-8 from keratinocytes, resulting from the interaction between C. acnes and TLR-2 on the cellular membrane, has been recognized to play a fundamental role in the pathogenesis of inflammatory acne [ 30 , 31 ].…”

“…The traditional use of tannins, including HT, for antibacterial purposes, was sustained by scientific evidence regarding staphylococcal infections [ 22 , 33 ]. However, to our knowledge, Hamamelis virginiana L. or pure HT have never been investigated against C. acnes proliferation.…”

“…In line with this hypothesis, ECG—intended as a pharmacophore of the galloylated-proanthocyanidins—inhibited the NF-κB-driven transcription induced by TNF-α at low μM levels. Moreover, neither HVE (1000 μg/mL) nor HT (25 μg/mL) counteracted the growth of C. acnes , although the antibacterial effect is one of the main activities attributed to Hamamelis virginiana L., previously demonstrated versus staphylococcal and streptococcal species [ 22 ]. However, this work neither allows excluding the synergistic effects of tannin components for the bioactivity nor the role of HT in other biological contexts.…”

“…Two preliminary studies on human cultured keratinocytes suggested the possible role of gallotannins and proanthocyanidins in the antioxidant and cytoprotective effects of hamamelis bark extract [ 16 , 21 ]. In addition, witch hazel extract showed antibacterial activity in vitro [ 22 , 23 ].…”

Antibacterial Activity of Medicinal Plants and Their Constituents in the Context of Skin and Wound Infections, Considering European Legislation and Folk Medicine—A Review

“…Cheesman et al (2021) tested the antibacterial activity of different H. virginiana extracts on different species of streptococci and staphylococci. They found the methanolic and aqueous extracts effective in inhibiting the growth of S. epidermidis and S. aureus , with MIC values between 200 and 500 μg/mL [ 98 ].…”