Introduction
This study aimed to evaluate the potential of whole human saliva as an anti-acne agent against bacteria responsible for acne vulgaris (AV). Human saliva was selected due to its physiological and antioxidant properties, containing beneficial secretory molecules such as proline-rich proteins, mucins, secretory immunoglobulin A, lysozyme, lactoferrin, and amylase. Notably, the use of saliva to treat wounds and skin issues like pimples is common in Indian households, and it is a natural behavior observed in animals who instinctively lick their wounds for healing. Given saliva’s longstanding role in diagnostics and its rich composition of antimicrobial proteins, this study explores its effectiveness as a natural anti-acne treatment.
Materials and Methods
Whole saliva samples were collected from four individuals at three distinct intervals. These samples were used to perform antimicrobial susceptibility test (AST) against the pathogens. The Kirby–Bauer disk diffusion susceptibility test assessed the bacteria’s susceptibility to saliva, while the broth dilution method with Resazurin dye was employed to determine the minimum inhibitory concentration (MIC) of saliva against C. acnes and S. epidermidis.
Key Findings
- Diurnal Variation in Antibacterial Potency: Afternoon saliva demonstrated the strongest antibacterial activity against C. acnes and S. epidermidis, potentially due to diurnal shifts in saliva pH. Morning saliva, with a more acidic pH (5.5–6.5), showed less consistent effectiveness compared to the closer-to-neutral pH of afternoon samples (pH 6–7), which correlated with enhanced antibacterial action. This suggests that pH variations throughout the day may influence saliva’s antimicrobial potency.
- Role of Salivary Components: The effectiveness of saliva in reducing bacterial activity is attributed to several antimicrobial proteins present in saliva, including lactoferrin (Lf), lysozyme (Lz), salivary peroxidase, and various antimicrobial peptides. These proteins work through distinct mechanisms such as inhibiting biofilm formation, disrupting bacterial cell walls, and inactivating essential bacterial enzymes.
- Additional Benefits of Saliva in Wound Healing: Saliva contains growth factors that may enhance wound healing, potentially helping to reduce acne scars. Components like epidermal growth factor and histatins promote re-epithelialization and cell adhesion, suggesting that saliva not only reduces bacterial activity but also may aid in healing acne-related skin damage.
- Impact on Sebum and Inflammation: Topical application of saliva has shown to decrease sebum, likely due to the presence of the enzyme lipase, which breaks down lipids. This reduction in sebum could limit nutrient sources for acne bacteria, further inhibiting bacterial growth. Anti-inflammatory effects of components like lactoferrin also contributed to a decrease in acne inflammation.
Conclusions
This study highlights whole human saliva’s promising antibacterial properties, particularly afternoon samples, in reducing the activity of C. acnes and S. epidermidis. These findings emphasize saliva’s potential role as a natural treatment for acne, though further studies are needed to assess its efficacy in biofilm inhibition and its effects in vivo. Future research could broaden sample inclusion criteria, test biofilm reduction properties more extensively, and examine the influence of diurnal variation on salivary composition and antimicrobial potency.
Link to the study: https://tinyurl.com/46pcujxc
