In Vitro: Cytotoxicity, Apoptosis and Ameliorative Potential of Lawsonia inermis Extract in Human Lung, Colon and Liver Cancer Cell Line.

Cancer has emerged as a major public health issue in developed as well as in developing countries. Plant-derived molecules are widely being used in the treatment of cancer due to their minimum side effects. Lawsonia inermis (Henna) is one of the medicinal plants containing many therapeutic properties. In the present study, bioactive components of L. inermis extract were analyzed by LCMS/MS method and validated. Lawsone (3.5%) is primarily responsible for cytotoxic and anti-cancerous activities. These properties were studied on human lung carcinoma (A549), colorectal cancer (DLD1) and Hepatocellular carcinoma (HepG2) cancer cell lines. The activities were assessed by MTT assay, evaluation of apoptosis by measuring the production of Reactive Oxygen Species (ROS) and mitochondrial membrane potential of the cancer cell lines. Moreover, apoptosis in the respective cancer cell lines was also determined by chromatin condensation and DNA fragmentation using Hoechst 33528 and propidium iodide (PI) staining. The preliminary in vitro result of MTT showed that the henna extract induces cytotoxic properties against A549, DLD1, HepG2 with IC50values 490, 480 and 610 µg/ml respectively (more than 40% growth inhibition). In addition, the extract induced a concentration-dependent rise in ROS production which was 84, 102, and 110% in HepG2, DLD1 AND A549 respectively at 300 µg/ml, whereas at 400 µg/ml concentration it was 86, 102, and 106% in respective cell lines while decreasing mitochondrial membrane potential was more than 20% in the investigated cell lines. The extract also provoked changes associated with apoptosis and the data indicate that the ROS production leads to a diminution in mitochondrial membrane potential and this correlated with the extract cytotoxicity.

4-Hydroxyisoleucine improves insulin resistance by promoting mitochondrial biogenesis and act through AMPK and Akt dependent pathway.

4-Hydroxyisoleucine (4-HIL) is an unusual amino acid isolated from fenugreek seeds (Trigonella foenum graecum L). Various studies have shown that it acts as an antidiabetic agent yet its mechanism of action is not clear. We therefore investigated the effect 4-HIL on the high fructose diet fed streptozotocin induced diabetic rats and L6 myotubes. 4-HIL (50 mg/kg) has improved blood lipid profile, glucose tolerance and insulin sensitivity in a diabetic rat model. It has increased the glucose uptake in L6 myotubes in AMPK-dependent manner and upregulated the expression of genes (PGC-1α, PGC-1ß, CPT 1 and CPT 2), which have role in mitochondrial biogenesis and energy metabolism in the liver, skeletal muscles as well as in L6 myotubes. Interestingly, it also increased the AMPK and Akt expression along with their phosphorylated forms in the liver and muscle tissues of treated animals. Altogether we concluded that 4-HIL acts to improve insulin resistance by promoting mitochondrial biogenesis in high fructose diet fed STZ induced diabetic rats.

Synthesis and biological evaluation of chalcones as potential antileishmanial agents.

Antileishmanial activities of thirty-five synthetic chalcones have been examined. Among them, ten compounds (4, 6, 16, 22, 23, 24, 25, 29, 35 and 37) exhibited potent in vitro activity (IC50 range from 1.70 to 8 µM) against extracellular promastigotes and intracellular amastigotes form of Leishmania donovani. Two promising compounds 22 and 37 were tested in vivo in L. donovani/hamster model. Chalcone 37 showed 83.32% parasite inhibition at a dose of 50 mg/kg for 10 days whereas, 75.89% parasite inhibition at 100 mg/kg dose for 5 days by intraperitoneal route at day 7 post-treatment.

Synthesis, structure-activity relationships, and biological studies of chromenochalcones as potential antileishmanial agents.

Antileishmanial activities of a library of synthetic chalcone analogues have been examined. Among them, five compounds (11, 14, 16, 17, 22, and 24) exhibited better activity than the marketed drug miltefosine in in vitro studies against the intracellular amastigotes form of Leishmania donovani. Three promising compounds, 16, 17, and 22, were tested in a L. donovani/hamster model. Oral administration of chalcone 16, at a concentration of 100 mg/kg of body weight per day for 5 consecutive days, resulted in >84% parasite inhibition at day 7 post-treatment and it retained the activity until day 28. The molecular and immunological studies revealed that compound 16 has a dual nature to act as a direct parasite killing agent and as a host immunostimulant. Pharmacokinetics and serum albumin binding studies also suggest that compound 16 has the potential to be a candidate for the treatment of the nonhealing form of leishmaniasis.

Synthesis of novel anticancer iridoid derivatives and their cell cycle arrest and caspase dependent apoptosis.

Nyctanthes arbortristis Linn (Oleaceae) is widely distributed in sub-Himalayan regions and southwards to Godavari, India commonly known as Harsingar and Night Jasmine. In continuation of our drug discovery programme on Indian medicinal plants, we isolated arbortristoside-A (1) and 7-O-trans-cinnamoyl 6ß-hydroxyloganin (2) from the seeds of N. Arbortristis, which exhibited moderate in vitro anticancer activity. Chemical transformation of 2 led to significant improvement in the activity in derivative 8 and 15 against HepG2 (human hepatocellular carcinoma), MCF-7 (breast adenocarcinoma) cell lines. The compounds 8 and 15 were also capable of cell cycle arrest and caspase dependent apoptosis in HepG2 cell lines. These iridoid derivatives hold promise for developing safer alternatives to the marketed drugs.

Synthesis and insight into the structure-activity relationships of chalcones as antimalarial agents.

Licochalcone A (I), isolated from the roots of Chinese licorice, is the most promising antimalarial compound reported so far. In continuation of our drug discovery program, we isolated two similar chalcones, medicagenin (II) and munchiwarin (III), from Crotalaria medicagenia , which exhibited antimalarial activity against Plasmodium falciparum . A library of 88 chalcones were synthesized and evaluated for their in vitro antimalarial activity. Among these, 67, 68, 74, 77, and 78 exhibited good in vitro antimalarial activity against P. falciparum strains 3D7 and K1 with low cytotoxicity. These chalcones also showed reduction in parasitemia and increased survival time of Swiss mice infected with Plasmodium yoelii (strain N-67). Pharmacokinetic studies indicated that low oral bioavailability due to poor ADME properties. Molecular docking studies revealed the binding orientation of these inhibitors in active sites of falcipain-2 (FP-2) enzyme. Compounds 67, 68, and 78 showed modest inhibitory activity against the major hemoglobin degrading cysteine protease FP-2.