Bioactivity of Kaffir lime (Citrus hystrix DC.) leaf extract on gingivitis

Abstract

Gingivitis is an inflammatory condition of the gingival tissue. The treatment focuses on both reducing inflammation and removing dental plaque. Chlorhexidine mouthwash is one of the effective choices used as anti-plaque in dental care. However, long-term usage can cause several side effects. This study aimed to develop a safer mouthwash containing Citrus hystrix DC. (kaffir lime, KL) leaf extract, and elucidate the mechanism of action in terms of anti-inflammatory and anti-Candida activities. This study identified the active compound, lupeol that can inhibit the production of pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α), the expression of NF-κB- and NLRP3-associated genes (NOS2, NFKB1, IL1B, IL18, NLRP3, and PYCARD) and proteins (COX-2, phospho-IκBα, and NF-κB p65) in macrophages. Additionally, the proteomic analysis revealed proteins that might be involved in the anti-Candida activity under β-citronellol treatment, including oxidative stress response (Sod1p, Gst2p, and Ddr48p), cell wall (Als2p, Rbt1p, and Pga4p), and ATP synthesis-associated proteins (Atp3p, Atp7p, Cox1p, and Cobp). Finally, the mouthwash containing KL leaf extract was developed, and the efficacy was evaluated in 47 participants with mild-to-moderate gingivitis. The reduction of GI, PI scores, and the colony counts of Staphylococcus spp. and Candida spp. were found after 14-day usage. From the results, the mouthwash showed the potential to be used in conjunction with proper oral hygiene to help alleviate gingivitis.

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