Antioxidant and anti-inflammatory properties of Stingless bee-derived propolis against acne

By Bhavana KunkalikarReviewed by Benedette Cuffari, M.Sc.Nov 29 2022

In a recent study published in the Fitoterapia journal, researchers explore the anti-acne, antioxidant, and anti-inflammatory properties of Stingless bee (Tetragonula biroi)-derived propolis.

Study: Antioxidant, anti-inflammatory and anti-acne activities of stingless bee (Tetragonula biroi) propolis. Image Credit: grafvision / Shutterstock.com

What is propolis?

Propolis has been utilized in toothpaste, lotions, mouthwashes, drops, nutritional supplements, as well as antipyretic, anti-putrefactive, antiseptic, and wound-healing agents. Some stingless bee propolis products have been shown to encourage hair development, treat asthma, block the alpha-glucosidase enzyme, exert toxic effects against cancer cells, and act as antivirals against the herpes simplex virus.

About 80% of both adults and adolescents experience acne, which is a chronic form of skin inflammation that is often triggered by P. acnes. Due to the inflammatory nature of this condition, the researchers of the current study sought to determine the anti-acne potential of T. biroi propolis.

About the study

In the present study, researchers investigate the anti-acne, antioxidant, and anti-inflammatory characteristics of propolis extracts.

The antioxidant and antibacterial activities of T. biroi propolis were tested after their collection and extraction. Thin layer chromatography (TLC) was used to isolate active compounds, which was followed by nuclear magnetic resonance (NMR) analysis for their structural characterization. Several chemicals including nymphaeol A, 3'-O-methyldiplacone and 5,7,3',4'-tetrahydroxy-6-geranyl flavonol were identified.

Subsequently, patients and healthy individuals provided blood samples that were acquired through venipuncture. The erythrocyte membrane stabilization technique was used to assess the in vitro anti-inflammatory effects of the compounds. The percentage of membrane hemolysis was also determined.

Study findings

The antioxidant activity of the T. birori extract was measured by the α, α-diphenyl-β-picryl hydrazyl (DPPH) assay at doses of 6.25, 12.5, 25, 50, and 100 µg/ml, with respective values of 82.31, 89.36, 89.76, 96.28, and 98.27%. At 100 µg/ml, ascorbic acid served as a positive control, with a concentration of 91.97%.

When tested against P. acnes, 125, 250, and 500 µg/well T. birori extract resulted in inhibition zones measuring 15.70, 15.40, and 17.00 millimeters (mm), respectively. The positive control chloramphenicol elicited an inhibition zone of 33.40 mm when a dose of 10 µg/well was provided.

Previously, T. biroi has been shown to inhibit cell growth in breast, colon, and cervical cancer cells, elicit anti-inflammatory properties in a mouse model, exert antimicrobial effects against Bacillus cereus, Escherichia coli, Candida krusei, Pseudomonas aeruginosa, Staphylococcus aureus, and Penicillium chrysogenum, as well as inhibit severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) protease activity.

The antioxidant half maximal inhibitory concentration (IC₅₀) for 12, 3'-O-methyldiplacone was the highest with 17.32, as compared to 15.49, 41.85, and 6.23 micrometers (µM) for 5,7,3',4'-tetrahydroxy-6-geranyl flavonol, nymphaeol A, and the positive control of ascetic acid, respectively. Anti-inflammatory IC₅₀ values for 3'-O-methyldiplacone and nymphaeol A were comparable, whereas those for 5,7,3',4'-tetrahydroxy-6-geranyl flavonol were slightly higher at 121.45, 121.28, and 117.15 µM, respectively.

The 3'-O-methyldiplacone compound was not capable of preventing the development of P. acnes at concentrations of 0.125, 0.25, 0.5, and 1 µg/well. Comparatively, at 0.125, 0.25, 0.5, and 1 µg/well concentrations, nymphaeol A inhibited the development of P. acnes, with the inhibition zone measuring 11.11, 11.44, 11.78, and 14.11 mm, respectively. While 5,7,3',4'-tetrahydroxy-6-geranyl flavonol reduced P. acnes growth at 0.5 and 1 µg/well concentrations, the respective inhibition zones measured 9.78 and 13.78 mm.

About 10 µg/well of chloramphenicol produced an inhibitory zone of 30.44 mm. The team hypothesized that the growth inhibition of P. acnes, as well as the anti-inflammatory and antioxidant characteristics of the isolated compounds, could influence the presence of OH in C-3 and CHO₃ in C-3' and stereochemistry. This hypothesis requires additional testing for clarification.

Conclusions

Overall, the study findings showed that the proplis extracts of nymphaeol A, 3'-O-methyldiplacone, and 5,7,3',4'-tetrahydroxy-6-geranyl flavonol are potent agents that have potential cosmetic applications due to their antioxidant, anti-inflammatory, and anti-acne properties. In order to determine the efficacy and safety of these extracts, additional research is needed.