Cancer develops due to an imbalance between cell proliferation and cell death. Various mechanisms of carcinogenesis as well as of novel anticancer agents that could be targeted for the treatment of cancer have been proposed by different studies. Among these, p21 is recognized as a potent cyclin-dependent kinase inhibitor that facilitates cell-cycle arrest by interacting with different stimuli such as p53, DNA repair process, CDK, E2F1, MYC, PCNA, STAT3 AP4, proteasomes, K1F, CDX2, and ER-α. p21 acts both as a tumor-suppressor gene and an inhibitor of apoptosis by interacting with various molecules and transition factors. In this review, we discuss the complex role of p21 in the development of cancer and as a target in its treatment. We conclude that, in the future, the tumor-suppressor activity of p21 should be the focus of a novel treatment strategies, which may lead to the devolvement of new and selective anti-cancer agents for the targeted therapy of cancers.

Natural product studies explore potential and interesting new compounds to discover innovative drugs. Nigella sativa (N. sativa) (Ranunculaceae) is traditionally used to treat diabetes. Flavonoids and triterpenoid mostly show anti-diabetic activity. The current study aim to identify new compounds by a systematic study of the anti-oxidant and anti-diabetic activity of aerial parts of N. sativa concerning. Phytochemicals were isolated from the methanolic extract of aerial parts of the plant by column chromatography and identified by nuclear magnetic resonance spectroscopy and mass spectroscopy. A new triterpenoid saponin glycoside was isolated along with flavonoids. The anti-diabetic study was carried out by DPPH, ABTS, α -glucosidase, and protein tyrosine phosphatase 1B assays at doses of 12.5 to 250 µM. The isolated phytochemicals were identified as 3-O-(β-d-xylopyranosyl-(1-3)-α-l-rhamnopyrnaosyl-(1-2)-α-l-arabinopyranosyl]-28-O-(α-l-rhamno-pyranosyl-(1-4)-β-d-glucopyranosyl-(1-6)-β-d-glucopyranosyl] hederagenin (1), flaccidoside III (2), catechol (3), quercetin-3-gentiobiosides (4), magnoflorine (5), nigelflavonoside B (6), nigelloside (7), quercetin sphorotrioside (8), kaempferol-3, 7-diglucoside (9), kaempferol 3-O-rutinoside (10), rutin (11), 3-O-[α-l-rhamnopyranosyl-(1→2)-α-l-arabinopyranpsylhederagenin (12), 3β,23,28-trihydroxyolean-12-ene-3-O-α-l-arabinopyranoside(1→4)-a-rhamnopyranosyl,(1→4)-β-d-gluco-pyranoside (13), 3-O-α-l-rhamnopyranosyl-(1→2)-α-l-arabinopyranpsyl]-28-O-β-d-gluco-pyranosyl hederagenin (14), and α-hederin (15). These were isolated and are reported for the first time in this study. Compared 13 was identified as a new compound. Compound 2 was isolated for first time from the genus Nigella. Compound 6 was found to be the most active in the DPPH, and ABTS assays and compound 10 was found to be the most active in the α-glucosidase assay, with IC50 32.7 ± 0.1, 95.18 ± 0.9, 214.5 ± 0.0 µΜ, respectively. Compound 12, at a dose of 125 µΜ, showed anti-diabetic activity in a PTP1B assay with IC50 91.30 ± 2.5 µΜ. In conclusion, the anti-diabetic activity of N. sativa is due to its flavonoids and TTSGs. Therefore, our studies suggest that the aerial parts of N. sativa are also a valuable and alternate source of valuable phytochemicals that could be used to develop anti-oxidant and anti-diabetic medicines.

In the biological system, reactive oxygen species (ROS) play a crucial role in the defense mechanisms of the body. ROS is responsible for the initiation of several cellular responses that can impart the harmful effects on the body, initiating biomolecular damage. Therefore, it is essential to counteract the dangerous effects produced by ROS, which is only possible through the use of antioxidants. Researchers are evaluating medicinal plants to discover and investigate the new antioxidant sources. Using natural antioxidants, beneficial effects on human health can be achieved. In this article, we summarize the recent investigations of the sources of naturally occurring antioxidants.

For the treatment of several types of cancers, tumors and malignancies, scientists are investigating natural sources to discover novel therapeutic agents from medicinal plants having diverse anticancer properties. Research on natural products is being conducted to identify unexplored phytochemical constituents that have been proven to have diverse pharmacological activities. Several medicinal plants have been reported to regulate the progression of different types of cancers, tumors, and malignancies. In this article, we briefly summarize the recent progress in exploring the anticancer properties of various medicinal plants reported to modulate the expression of p53 and the induction of apoptosis. These plants provide a rich source of chemo-protective agents that can ultimately be used to manage cancer progression.

Aim:The main aim of the study is to investigate the phytochemical screening of C. decapetala along with the content determination of different species of genus Caesalpinia with respect to their antidiabetic activity and identification of most bioactive species belonging to different origins. Methods: To achieve our goal different species of genus Caesalpinia collected from China and Pakistan were subjected to open column chromatography, High Pressure Liquid Chromatography (HPLC), antioxidant, and antidiabetic assays for evaluation. Results: From η-BuOH fraction of C. decapetala extract, eight compounds were isolated using open column chromatography and identified as apigenin-7-rhamnoside (1), 4-O-methylepisappanol (2), caesalpinol (3), daucosterol (4), astragalin (5), kaempferol (6), quercitrin (7), and naringin (8) using Nuclear Magnetic Resonance (NMR) spectroscopy. HPLC analysis of different species of genus Caesalpinia showed that the most active antidiabetic compound 'quercitrin' was present more in C. pulcherrima followed by decreasing order in C. sappan, C.decapetala, and C. bonduc. Conclusion: The results indicated that quercitrin is the most bioactive content and C. pulcherrima is most bioactive specie of China origin from genus Caesalpinia.