Castor Oil for Antimicrobial

Castor oil, a vegetable oil derived from the castor bean plant, has been investigated in several clinical trials and randomized controlled trials (RCTs) for its potential antimicrobial properties. This exploration stems from traditional uses of castor oil for wound healing and infection management, suggesting a possible role in combating microbial infections. Further research is needed to fully elucidate the mechanism and efficacy of castor oil's antimicrobial effects.

Protocols Studied in Research

[1] Sodium hypochlorite (0.1% and 0.2%) and *Ricinus communis* solutions for denture biofilm and denture stomatitis. (Cited by: 8) (pmid: 27927282)

• Protocol: A randomized crossover clinical trial involving 50 denture wearers with denture stomatitis. Participants soaked dentures in four solutions (control saline, 0.1% sodium hypochlorite, 0.2% sodium hypochlorite, 8% *Ricinus communis*) for 20 minutes daily over 14 days. Biofilm and *Candida* levels were assessed.
• Outcome: 0.1% and 0.2% sodium hypochlorite solutions were most effective in reducing denture biofilm. All solutions reduced denture stomatitis signs, with sodium hypochlorite showing the strongest effect.

[2] Castor oil extract as root canal irrigant for reducing *E. coli* and endotoxins. (Cited by: 6) (pmid: 22782052)

• Protocol: In vitro study using 60 single-rooted teeth. Teeth were instrumented with castor oil extract and then treated with one of five solutions (castor oil extract, Ca(OH)2, polymyxin B, Ca(OH)2+CHX, or saline). Endotoxin and bacterial counts were measured at four time points.
• Outcome: Castor oil extract reduced *E. coli* counts but not endotoxin levels. Ca(OH)2+CHX and castor oil extract showed significant endotoxin reduction seven days post-medication removal. No treatment completely eliminated endotoxins.

[3] Sodium hypochlorite (0.25% and 0.5%) and Ricinus communis (10%) solutions for controlling denture biofilm and associated microorganisms (Streptococcus mutans, Candida spp., gram-negative bacteria). (Cited by: 18) (pmid: 26814466)

• Protocol: A randomized clinical trial involving 64 complete denture wearers. Participants soaked their dentures in one of four solutions (0.25% sodium hypochlorite, 0.5% sodium hypochlorite, 10% R. communis oil, or saline control) for 20 minutes daily for 7 days, with a 1-week washout between solutions. Biofilm was assessed via CFU counts.
• Outcome: 0.5% sodium hypochlorite was the most effective solution against all tested microorganisms. Ricinus communis and 0.25% sodium hypochlorite also showed antimicrobial activity, but less than 0.5% sodium hypochlorite. *Candida albicans* was the most prevalent Candida species.

Research Interpretation: Summary and Conclusion

Three studies investigated the antimicrobial properties of *Ricinus communis* (castor oil) against oral biofilms and bacteria. Two studies used *R. communis* in denture soaking solutions, comparing its efficacy to sodium hypochlorite, while one study assessed its in vitro effect on endotoxin and *E. coli* in instrumented teeth. While castor oil demonstrated some antimicrobial activity, reducing *E. coli* counts in one study and showing modest biofilm reduction in another, its effectiveness was consistently less than that of sodium hypochlorite. The studies varied in their protocols, including the concentration of castor oil used, the duration of treatment, and the specific microorganisms targeted. In summary, the evidence suggests that castor oil possesses limited antimicrobial properties compared to established antimicrobials like sodium hypochlorite, warranting further research to determine its potential role in specific clinical applications. Further investigation is needed to optimize its concentration and application method for improved efficacy.

Publications

[1] Arruda CNF; Salles MM; Badaro MM; de Cassia Oliveira V; Macedo AP; Silva-Lovato CH; de Freitas Oliveira Paranhos H (2017). Effect of sodium hypochlorite and Ricinus communis solutions on control of denture biofilm: A randomized crossover clinical trial The Journal of prosthetic dentistry 117 (6) :729-734.

[2] Valera MC; Maekawa LE; Chung A; de Oliveira LD; Carvalho CA; Koga-Ito CY; Jorge AO (2012). Effectiveness of castor oil extract on Escherichia coli and its endotoxins in root canals General dentistry 60 (4) :e204-9.

[3] Salles MM; Badaro MM; Arruda CN; Leite VM; Silva CH; Watanabe E; Oliveira Vde C; Paranhos Hde F (2015). Antimicrobial activity of complete denture cleanser solutions based on sodium hypochlorite and Ricinus communis - a randomized clinical study Journal of applied oral science : revista FOB 23 (6) :637-42.