Cytotoxic, Antibacterial, and Antioxidant Activities of the Leaf Extract of Sinningia bullata

Abstract

Sinningia bullata is a tuberous member of the flowering plant family Gesneriaceae. Prior to this work, the antibacterial, antioxidant, and cytotoxic properties of S. bullata were undetermined. Here, we prepared different extracts from the leaf, stem, and tuber of S. bullata and investigated their pharmacological activities. The leaf extract of S. bullata, obtained by 100% acetone (Sb-L-A), had the highest total flavonoid content, antioxidation capacity, and cytotoxic and antibacterial activities. Sb-L-A displayed a broad range of antibacterial activities against Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. The inhibition zones of Sb-L-A ranged from 8 to 30 mm and were in the following order: S. aureus > E. coli > P. aeruginosa. Incubation of B16F10 melanoma cells with Sb-L-A at a concentration of 80 μg/mL caused deaths at the rate of 96%, reduced migration by 100%, suppressed proliferation and colony formation by 99%, and induced apoptosis, which was observed in 96% of the B16F10 cells. In addition, the cytotoxic activities of Sb-L-A were synergistically enhanced when coacting with the antitumor drug epothilone B. Sb-L-A was also used to determine the cytotoxic effects against 4T1 mammary carcinoma cells. Sb-L-A of 60 μg/mL boosted the distribution of the G2 phase from 1.4% to 24.4% in the B16F10 cells. Accordingly, Sb-L-A might suppress melanoma cell proliferation by inducing G2 cell-cycle arrest. The most abundant compounds in Sb-L-A were identified using gas chromatography–mass spectrometry. The top two contents in this extract were adlupulone and villosin. Overall, the collective data in this study may indicate the pharmacological potentials of Sb-L-A for possible medical applications.

The Inhibitory Effects and Cytotoxic Activities of the Stem Extract of Nepenthes miranda against Single-Stranded DNA-Binding Protein and Oral Carcinoma Cells

“…Like the stem extract of N. miranda, the leaf extract of S. bullata also exhibited cytotoxicity in regard to cancer cell survival, migration, and proliferation, and induced apoptosis in cancer cells [37]. However, their contents, as tentatively identified via GC-MS, were found to be significantly different.…”

“…Thus, the cytotoxic mechanisms may differ between these two extracts. Plumbagin, a major active compound in the stem extract of N. miranda, was not found in the leaf extract of S. bullata [37], but other naphthoquinones such as 7,8-dimethoxydunnione [52] and aggregatins [53] were found in the tuber extracts of similar Sinningia species. These and other naphthoquinones could possibly be useful in combination for further anticancer drug development.…”

“…We screened different plant extracts of N. miranda and Sinningia bullata for a KpSSB inhibitor. S. bullata is a tuberous member of the flowering plant family Gesneriaceae [36,37]. Leaf, stem, and pitcher of N. miranda and leaf, stem, and tuber of S. bullata were extracted using 100% methanol to assess whether these extracts inhibit KpSSB activity (Figure 4).…”

“…The E. coli strains TOP10F' (Invitrogen, Waltham, MA, USA) and BL21(DE3) pLysS (Novagen, Worcestershire, UK) were used for genetic construction and protein expression, respectively. The cell lines Ca9-22 gingival carcinoma, CAL27 oral adenosquamous carcinoma, PC-9 pulmonary adenocarcinoma, B16F10 melanoma, and 4T1 mammary carcinoma were obtained from Food Industry Research and Development Institute, Hsinchu, Taiwan [16,18,37,45,55,56]. Ca9-22, CAL27, B16F10 and 4T1 cells were maintained as a monolayer culture in Dulbecco's modified Eagle medium (GibcoTM; Thermo fisher Scientific, Waltham, MA, USA) supplemented with 10% fetal bovine serum (FBS), 100 unit/mL penicillin, and 100 µg/mL streptomycin.…”

Correction: Chen et al. Cytotoxic, Antibacterial, and Antioxidant Activities of the Leaf Extract of Sinningia bullata. Plants 2023, 12, 859

“…The authors would like to supplement some methodology information including the controls in the originally published version of this manuscript [1]. The ingredients of the leaf extract of S. bullata tentatively identified using GC-MS are also revised in this correction.…”