The adhesion of early settlers of dental plaque to the tooth surface has a role in the initiation of the development of dental plaque. The hydrophobic surface properties of the bacteria cell wall are indirectly responsible for the adhesion of the bacteria cell to the acquired pellicle on the tooth surfaces. In this study, the effect of aqueous extract of two plants (Psidium guajava and Piper betle) on the cell-surface hydro-phobicity of early settlers of dental plaque was determined in vitro. Hexadecane, a hydrocarbon was used to represent the hydrophobic surface of the teeth in the oral cavity. It was found that treatment of the early plaque settlers with 1 mg/ml extract of Psidium guajava reduced the cell-surface hydrophobicity of Strep. sanguinis, Strep. mitis and Actinomyces sp. by 54.1%, 49.9% and 40.6%, respectively. Treatment of these bacteria with the same concentration of Piper betle however, showed a comparatively lesser effect (< 10%). It was also observed that the anti-adhesive effect of the two extracts on the binding of the early plaque settlers to hexadecane is concentration dependent. (J. Oral Sci. 48, 71-75, 2006)

Nigella sativa, Melastoma malabathricum, Pluchea indica, and Piper sarmentosum are common Asian traditional medicines to treat minor wounds. This study aimed to investigate the in vitro wound healing properties of aqueous extracts of these plants using human gingival fibroblast (HGF) monolayer as study model. DPPH scavenging activity of the extracts was evaluated and effect on HGF proliferation was determined. Their effect on HGF’s function to synthesize collagen was indicated by the level of hydroxyproline produced and effect on wound healing activity was assessed using an in vitro scratch assay. The influence of the extracts on expression of bFGF and TGF‐β was also determined. Results revealed all four extracts to exhibit low free radical scavenging activity. The extract from N. sativa (NSSE) compared to the others showed favourable enhancement of HGF proliferation with EC₅₀ of 22.67 ± 3.06 µg/mL (P < 0.05) with accelerated wound closure activity despite its nonsignificant effect on collagen synthesis. In addition to the elevated level of bFGF by up to 15% at 100 µg/mL of NSSE, a slightly better effect was observed on the expression of TGF‐β. NSSE thus showed that promising wound healing properties and data obtained may contribute towards validation of its traditional use for the healing of oral wounds.

Cancers involving the oral cavity, head, and neck regions are often treated with cisplatin. In cancer therapy, the main target is to eliminate unwanted cancerous cells. However, reports on the nonselective nature of this drug have raised few concerns. Incorrect nutritional habits and lifestyle practices have been directly linked to cancer incidence. Nutrients with antioxidant activity inhibit cancer cells development, destroying them through oxidative stress and apoptosis. α-tocopherol, the potent antioxidant form of vitamin E is a known scavenger of free radicals. In vitro study exhibited effective antitumor activity of α-tocopherol on ORL-48 at 2.5 ± 0.42 µg/mL. Cisplatin exhibited stronger activity at 1.0 ± 0.15 µg/mL, but unlike α-tocopherol it exhibited cytotoxicity on normal human epidermal keratinocytes at very low concentration (<0.1 µg/mL). Despite the lower potency of α-tocopherol, signs of apoptosis such as the shrinkage of cells and appearance of apoptotic bodies were observed much earlier than cisplatin in time lapse microscopy. No apoptotic vesicles were formed with cisplatin, instead an increased population of cells in the holoclone form which may suggest different induction mechanisms between both agents. High accumulation of cells in the G0/G1 phase were observed through TUNEL and annexin V-biotin assays, while the exhibition of ultrastructural changes of the cellular structures verified the apoptotic mode of cell death by both agents. Both cisplatin and α-tocopherol displayed cell cycle arrest at the Sub G0 phase. α-tocopherol thus, showed potential as an antitumour agent for the treatment of oral cancer and merits further research.

Candida species have been associated with the emergence of resistant strains towards selected antifungal agents. Plant products have been used traditionally as alternative medicine to ease candidal infections. The present study was undertaken to investigate the antifungal susceptibility patterns and growth inhibiting effect of Brucea javanica seeds extract against Candida species.

Brucea javanica, Azadirachta indica,andTyphonium flagelliformeare medicinal plants commonly used to treat conditions associated with tumour formation. This study aimed to determine the antiproliferative activity of these plants extracts on KB and ORL-48 oral cancer cell lines and to suggest their mode of cell death. The concentration producing 50% cell inhibition (IC₅₀) was determined and the activity was examined under an inverted microscope. Immunohistochemistry fluorescent staining method (TUNEL) was performed to indicate the mechanism of cell death and the fragmented DNA band pattern produced was obtained for verification. Compared toAzadirachtasp. andTyphoniumsp., the antiproliferative activity ofBruceasp. extract was the most potent on both KB and ORL-48 cells with IC₅₀of 24.37 ± 1.75 and 6.67 ± 1.15 µg/mL, respectively. Signs of cell attrition were observed 24 hr after treatment. Green fluorescent spots indicating cell death by apoptosis were observed in images of both cells following treatment with all the three extracts. DNA fragments harvested fromBrucea-treated cells produced bands in a ladder pattern suggesting the apoptotic effect of the extract. It is thus concluded thatBruceasp. extract exhibited cytotoxic activity on ORL-48 cells and their action mechanism is via apoptosis.