Antifibrotic effect of Ocimum basilicum L. and linalool on arecoline-induced fibrosis in human buccal fibroblasts

Aim: To explore Ocimum basilicum L. (sweet basil) and linalool for their antifibrotic activity in an arecoline-induced in vitro fibrotic model. Methods: Leaf extract of O. basilicum L. (LEOB) and linalool were used as experimental agents to test their antifibrogenic activity in vitro. Half-maximal inhibitory concentration (IC50) for arecoline, ethanolic LEOB, and linalool was determined using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. To evaluate the antifibrotic effect of ethanolic LEOB and linalool on pretreatment, that is, both the testing agents were added to the human buccal fibroblasts (HBFs) prior to induction with arecoline, and reverse transcriptase polymerase chain reaction (RT-PCR) was carried out to study the response of transforming growth factor beta (TGFβ), collagen 1 subtype A2 (COL1A2), and collagen 3 subtype A1 (COL3A1). To appreciate the morphological alterations in HBFs on treatment with arecoline, ethanolic LEOB, and linalool, Masson’s trichrome staining was performed. Results: Arecoline enhanced fibrotic activity by upregulating TGFβ1, COL1A2, and COL3A1 levels, whereas ethanolic LEOB and linalool on pretreatment significantly downregulated the increased levels of TGFβ1, COL1A2, and COL3A1 in primary HBF cell cultures. Conclusion and implication to clinic: Both ethanolic LEOB and linalool exhibited significant antifibrotic activity in an in vitro model. Further studies in an in vitro model can help attain a foundation for an herbal formulation in gel form that can be prescribed to patients diagnosed with oral submucous fibrosis for topical application. It can also be used synergistically with Western medicine.