A review of the antimicrobial potential of herbal drugs used in popular Italian medicine (1850s-1950s) to treat bacterial skin diseases

Ethnopharmacological relevance: Before the advent of modern antibiotics, microbial infections were treated with herbal medicine or cauterization. Literature from the latter half of the nineteenth to the early mid-twentieth century, when antibiotics became widely available, arguably holds the most progressive information about herbal remedies to treat bacterial skin diseases. The corpus of literature produced in Italy during that period is not easily accessible and mostly out of print. Material and methods: Plant-based remedies utilized in popular Italian medicine to treat anthrax, boils, erysipelas, impetigo, pustules, and whitlow were sourced from literature indexed in and available through the National Library Service website of the Italian Libraries Network. The remedies are assessed for their antimicrobial potential based on a detailed search of the herbal drug species in scientific databases. Results: A considerable part of the reviewed recipes included specific excipients (41 out of 139) and others were produced with fresh plant material (48 out of 139). Out of the 52 identified herbal drug species used in popular Italian medicine against dermatologic infections, extracts of 43 were shown to have moderate in vitro activity against Gram-positive and Gram-negative bacteria. Conclusion: The antibacterial activity of the extracts and pure compounds as reported in the reviewed literature is mostly based on in vitro assays and generally does not encourage follow up studies. The effectiveness of the reported recipes, which include fresh plant material and excipients can only be assessed through in vivo studies. Those remedies including herbal drugs with reported antimicrobial activity might have the potential as complementary therapies. The reviewed plant based antimicrobial recipes might serve as inspirations in the search for alternative topical antibacterial strategies and the search for their synergistic and potentiating ingredients.