Leaf extract of Osbeckia octandra induces apoptosis in oral squamous cell carcinoma cells

• Published in: BMC complementary and alternative medicine Vol. 22; no. 1; p. 20
• Main Authors: Kim, Jue Young, Kim, Jin, Bandara, B M Ratnayake, Tilakaratne, Wanninayake M, Kim, Dokyeong
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 25-01-2022; BioMed Central; BMC
• Subjects: Alternative medicine; Annexin V; Antibodies; Anticancer properties; Antineoplastic Agents, Phytogenic - pharmacology; Antineoplastic Agents, Phytogenic - therapeutic use; Apoptosis; Apoptosis - drug effects; BAX protein; Bcl-2 protein; Bcl-x protein; Cancer; Carcinoma, Squamous Cell - drug therapy; Care and treatment; Caspase-3; Caspase-8; Caspase-9; Cell activation; Cell cycle; Cell cycle arrest; Cell Line, Tumor - drug effects; Cell proliferation; Cyclin D1; Cytotoxicity; Deoxyribonucleic acid; DNA; DNA biosynthesis; DNA replication; Endemic plants; Evaluation; Flow cytometry; G1 phase; Humans; Keratinocytes; Leaves; Medicine, Botanic; Medicine, Herbal; Mouth Neoplasms - drug therapy; Myrtales; Oral cancer; Oral carcinoma; Oral squamous cell carcinoma; Osbeckia octandra; Phytotherapy; Plant extracts; Plant Extracts - pharmacology; Plant Extracts - therapeutic use; Proteins; Reactive oxygen species; Replication; Solvents; Squamous cell carcinoma; Sri Lanka; Tumor cell lines; Western blotting; Sri Lanka; Massachusetts; Netherlands; United Kingdom > UK; United States > US; Switzerland; Germany; Cell cycle arrest; Oral squamous cell carcinoma; Osbeckia octandra; Apoptosis
• ISSN: 2662-7671; 2662-7671; 1472-6882
• DOI: 10.1186/s12906-022-03505-4

Osbeckia octandra is a plant endemic to Sri Lanka and is used in ethnomedicine for treating various diseases. However, the anti-cancer properties of O. octandra are yet to be fully investigated. In the present study, we evaluated the anti-cancer effects of O. octandra on oral cancer cells.
Human oral cancer cell lines (HSC2, YD10B, YD38, YD9, and YD32) were used in this study. BrdU incorporation, cell cycle and annexin-V/PI staining were all evaluated using flow cytometry to determine the extent to which O. octandra leaf extract inhibits cell proliferation and induces apoptosis. Cell viability and reactive oxygen species (ROS) were also measured in order to investigate the anti-cancer effects of O. octandra extracts. Western blotting was performed to detect cell cycle related protein such as cyclin d1 and cdk4, and to detect apoptosis-related proteins such as Bcl-2, Bcl-X
, Bax, Caspase-9, Cleaved caspase-3, Fas, Caspase-8, and Bid.
Leaf extract of O. octandra reduced oral squamous cell carcinoma (OSCC) cell viability in a dose-dependent manner. Leaf extract of O. octandra has non-toxic in normal keratinocytes. Also, O. octandra extract interrupted the DNA replication via G1 phase arrests, and this effect was independent of ROS generation. In the apoptosis-related experiments, the population of annexin V-positive cells increased upon treatment with O. octandra extract. Furthermore, the expression of anti-apoptotic protein (Bcl-2 and Bcl-xL) was decreased, whereas the expression of cleaved caspase-3 protein was increased in O. octandra-treated OSCC cells.
The results suggest that a leaf extract of O. octandra inhibited the proliferation of OSCC cells through G
phase arrest and interrupting DNA replication. The leaf extract of O. octandra could trigger the apoptotic response via caspase 3 activation in OSCC cells. These results suggest that O. octandra has the potential to be developed as an alternative medicine for treating OSCC.