Efficacy of Calendula officinalis Extract (Marigold Flower) as an Antimicrobial Agent against Oral Microbes: An Invitro Study in Comparison with Chlorhexidine Digluconate

Abstract

Introduction: Calendula officinalis is a member of the family Asteraceae containing flavonoids, and essential oils etc. It is known to be effective against certain gram negative and gram positive clinical pathogens. Incorporating natural plant extracts into periodontal antiinfective therapy is a wise alternative in light of rampant antibiotic resistance amongst periodontal pathogens. Aim: To assess the antimicrobial efficacy of C.officinalis against five oral microbes, as compared to gold standard chlorhexidine digluconate. Materials and Methods: The inhibitory action of the two test agents, chlorhexidine digluconate 0.2% and C.officinalis raw extract was assessed using tests to determine minimum inhibitory concentration, minimum bactericidal concentration, and inhibition zones using agar diffusion method. Time kill curve method was used to assess the time in which drug was inhibitive against five oral microbes namely, A.actinomycetemcomitans, P.gingivalis, P.intermedia, F.nucelatum and S.mutans. Results: P.gingivalis and P.intermedia were sensitive to C.officinalis, while F.nucleatum and A.actinomycetemcomitans exhibited reduced sensitivity. C.officinalis was highly effective against S.mutans (3.12 µg/mL), its inhibitory concentration close to that of chlorhexidine digluconate 0.2% (6.25 µg/mL). C.officinalis took longer than chlorhexidine digluconate 0.2% to exhibit lethality against all the organisms that it inhibited. Chlorhexidine exhibited immediate lethality (zero minute) against S.mutans while it inhibited the other microbes at 5 minutes. A.actinomycetemcomitans and P.intermedia were inhibited by C.officinalis at 30 minutes, S.mutans at 10 minutes. F.nucleatum was inhibited by C.officinalis at 2 hours and no inhibition of P.gingivalis by C.officinalis was observed. Conclusion: C.officinalis showed antimicrobial efficacy against most organisms tested, yet its efficacy was not on par with chlorhexidine digluconate 0.2%. However, its performance could still be used as evidence to spur on further human clinical trials, in patients undergoing phase I or IV therapies.

Keywords

• Antibiotic resistance
• Anti-infective therapy
• Complementary/alternative medicine
• Non surgical periodontal therapy