Peristrophe bicalyculata (Retz) Nees contains principles that are cytotoxic to cancer cells and induce caspase-mediated, intrinsic apoptotic death through oxidative stress, mitochondrial depolarisation and DNA damage.

The plant Peristrophe bicalyculata (Retz) Nees is used for the treatment of cancer. While its leaf extracts have been shown to inhibit the growth of some cancer cells, there is little information supporting the constituents' anti-tumour potential. This study, therefore, investigated the effects of the plant's leaf extracts on cancer cells and the associated cellular/molecular mechanisms. Extracts were prepared using hexane (PBH), chloroform (PBC), ethyl acetate (PBE) and methanol (PBM) and constituents were identified by Liquid Chromatography-Mass Spectrometry (LC-MS). Their cytotoxic effects on human cervical (HeLa) and lung cancer (MRC5-SV2) cells were assessed using the MTT and LDH release assays. Reactive oxygen species (ROS) production was assessed using 2',7'-dichlorofluorescein diacetate (DCFDA) and mitochondrial membrane potential by staining with JC-1 (5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolyl-carbocyanine iodide). Caspase activation was determined using a Caspase-Glo-3/7 assay, and DNA damage by the Comet assay. Changes to mRNA expression were assessed using Quantitative Real-Time PCR. PBC, PBE and PBM reduced cell viability and induced LDH release, with IC50 values (48 h, MTT, in µg/ml), respectively, of 6.21 ± 0.70, 23.39 ± 3.92, and 22.43 ± 3.58 (HeLa); and 1.98 ± 0.33, 8.57 ± 1.91 and 28.24 ± 5.57 (MRC5-SV2). PBC induced ROS, while PBC, PBE and PBM impaired mitochondrial membrane potential and induced caspase 3/7 activation. PBC and PBE induced DNA damage, and PBE induced caspase-3 mRNA expression. Constituents of the extracts included derivatives of gallic acid, dipeptides, diterpenoids and flavones. We conclude that P. bicalyculata contains cytotoxic principles that could be potential leads for developing novel anti-cancer agents.

Chalcones: Synthetic Chemistry Follows Where Nature Leads.

Chalcones belong to the flavonoid class of phenolic compounds. They form one of the largest groups of bioactive natural products. The potential anticancer, anti-inflammatory, antimicrobial, antioxidant, and antiparasitic properties of naturally occurring chalcones, and their unique chemical structural features inspired the synthesis of numerous chalcone derivatives. In fact, structural features of chalcones are easy to construct from simple aromatic compounds, and it is convenient to perform structural modifications to generate functionalized chalcone derivatives. Many of these synthetic analogs were shown to possess similar bioactivities as their natural counterparts, but often with an enhanced potency and reduced toxicity. This review article aims to demonstrate how bioinspired synthesis of chalcone derivatives can potentially introduce a new chemical space for exploitation for new drug discovery, justifying the title of this article. However, the focus remains on critical appraisal of synthesized chalcones and their derivatives for their bioactivities, linking to their interactions at the biomolecular level where appropriate, and revealing their possible mechanisms of action.

Growth inhibitory activity of biflavonoids and diterpenoids from the leaves of the Libyan Juniperus phoenicea against human cancer cells.

Three biflavonoids [cupressuflavone (1), amentoflavone (2), and sumaflavone (3)], four diterpenoids [13-epi-cupressic acid (4), imbricatholic acid (5), 3-hydroxy-sandaracopimaric acid (6), and dehydroabietic acid (7)], and one lignan [ß-peltatin methyl ether (8)] were isolated from the cytotoxic fractions of the extracts of the leaves of the Libyan Juniperus phoenicea L. The structures of these compounds were elucidated by spectroscopic means. Cytotoxicity of compounds 1-6 were assessed against the human lung cancer cell line A549 using the MTT assay. Compounds 1 and 3 showed cytotoxicity against the A549 cells (IC50  = 65 and 77 µM, respectively), whereas compound 2 did not show any activity. Diterpenes 4-6 exhibited weak cytotoxicity against the A549 cells with the IC50 values of 159, 263, and 223 µM, respectively. The cytotoxicity of each compound was compared with the anticancer drug, etoposide (IC50  = 61 µM). Cupressuflavone (1) was evaluated also for cytotoxicity against both the human PC3 cancer cell line and the normal prostate cell line (PNT2), and this compound revealed a high degree of cytotoxic selectivity towards the prostate cancer cells (PC3), with IC50 value of 19.9 µM, without any evidence of cytotoxicity towards the normal prostate cell line (PNT2).