The Porphyromonas gingivalis inhibitory effects, antioxidant effects and the safety of a Sri Lankan traditional betel quid - an in vitro study

Elucidating the potential of Annona muricata L. grown in Sri Lanka to be used in developing an anticancer drug against colorectal and breast cancers

BACKGROUND

Since ancient times many traditional medicine systems around the world have been using different parts of Annona muricata L. (AM), to treat cancer. Indeed, numerous in vitro and in vivo studies also have shown anticancer properties of different solvent extracts of different parts of AM. Even the same part of the plant has shown different levels of anticancer properties based on geographical variations. Therefore, in the present study, the anticancer potential of the leaves, fruit pulp and the fruit peel of the AM that is grown in Sri Lanka was comparatively analyzed with the intention of identifying the most suitable part to be developed into a nutraceutical with anticancer effects.

METHODS

Freeze-dried aqueous extracts of immature leaves (ILAM), mature leaves (MLAM), pulp (PAM) and peel (PLAM) of AM were analyzed for their antioxidant activity using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging and 2,2-azinobis-3-ethylbenzothiozoline-6-sulfonic acid (ABTS) cation decolorization assays. Their cytotoxicity on breast cancer (MCF-7) cells, colorectal adenocarcinoma (DLD-1) cells and normal human gingival fibroblasts (HGF-1) were determined by the 3-(4,5- dimethylthiazole-2-yl)-2,5-diphenyl-tetrazoliumbromide (MTT) assay. Their effect on mRNA expression of proapoptotic (Bax and caspase-7) and cell cycle arresting (p21) genes was analyzed by RT- qPCR in the same cell lines.

RESULTS

ILAM demonstrated the highest antioxidant activity in both DPPH and ABTS assays followed by MLAM, PLAM and PAM. In the MTT assay, both ILAM and MLAM demonstrated strong cytotoxic activity against MCF-7 and DLD-1 cell lines while there were no cytotoxic effects on the normal human cell line HGF-1. Both ILAM and MLAM demonstrated concentration-dependent upregulation of mRNA expression of cell cycle arresting gene p21 and apoptosis inducing genes Bax and caspase-7 in MCF-7 and DLD-1 cells.

CONCLUSION

The AEAM leaves grown in Sri Lanka has significantly higher antioxidant activity as well as selective cytotoxic effects on MCF-7 and DLD-1 cancer cells compared to its PL and P counterparts. Further, the AEAM leaves induced mRNA expression of the anticancer genes p21, Bax and caspase-7, indicating its potential to be developed into an anticancer drug against breast and colorectal cancer.

Phytochemical Analysis, Antioxidant and Bone Anabolic Effects of Blainvillea acmella (L.) Philipson

Blainvillea acmella (L.) Philipson [Asteraceae] (B. acmella) is an important medicinal plant native to Brazil, and it is widely known as a toothache plant. A plethora of studies have demonstrated the antioxidant activities of B. acmella and few studies on the stimulatory effects on alkaline phosphatase (ALP) secretion from bone cells; however, there is no study on its antioxidant and anabolic activity on bone cells. The study aimed to evaluate the phytochemical contents of aqueous and ethanol extracts of B. acmella using gas chromatography mass spectrometry (GCMS) and liquid chromatography time of flight mass spectrometry (LCTOFMS) along with the total phenolic (TPC) and flavonoid (TFC) contents using Folin-Ciocalteu and aluminum colorimetric methods. The extracts of B. acmella leaves were used to scavenge synthetic-free radicals such as 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), and ferric reducing antioxidant power (FRAP) assays. The bone anabolic effects of B. acmella extracts on MC3T3-E1 cells were measured with 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazoium bromide (MTT) at 1, 3, 5, and 7 days, Sirius-red and ALP at 7 and 14 days, and Alizarin Red S at 14 and 21 days. Comparatively, ethanol extract of B. acmella (BaE) contributed higher antioxidant activities (IC₅₀ of 476.71 µg/ml and 56.01 ± 6.46 mg L-ascorbic acid/g against DPPH and FRAP, respectively). Anabolic activities in bone proliferation, differentiation, and mineralization were also higher in B. acmella of ethanol (BaE) than aqueous (BaA) extracts. Positive correlations were observed between phenolic content (TPC and TFC) to antioxidant (ABTS and FRAP) and anabolic activities. Conversely, negative correlations were present between phenolic content to antioxidant (DPPH) activity. These potential antioxidant and bone anabolic activities in BaE might be due to the phytochemicals confirmed through GCMS and LCTOFMS, revealed that terpenoids of α-cubebene, cryophyllene, cryophyllene oxide, phytol and flavonoids of pinostrobin and apigenin were the compounds contributing to both antioxidant and anabolic effects in BaE. Thus, B. acmella may be a valuable antioxidant and anti-osteoporosis agent. Further study is needed to isolate, characterize and elucidate the underlying mechanisms responsible for the antioxidant and bone anabolic effects.