A diseases, including cancer, atherosclerosis, malaria, and rheumatoid arthritis

A fairly common plant from 1500 to 3000 m in the Murree, Kaghan and Kashmir hills. The roots contain a resinoid substance, phytolaccin, which is used in medicine. They are also used to dilute belladonna. Their plants are shrubby, 1-2 m tall. Stem stout, fistular. Leaves lanceolate to ovate, 12-30 cm long, 4-10 cm broad; petioles short. Inflorescence of leaf is opposed, short peduncled raceme, up to 25 cm long. Flowers are greenish, 5 mm in diameter, pedicellate, bracteate. Bracts are linear. Bracteoles 2, linear. Perianth 5, polyphyllous, each oblong, obtuse. Stamens 10, persistent. Carpels 6 to 8, free; 1 basal ovule in each; style prominent. Fruit a cluster of dark purple berries. Seeds are compressed; testa almost black, glabrous. Flowering and fruiting time is from July to October and harvesting time is from September to November.Free radicals and other reactive oxygen species (ROS) are continuously produced in the human body. Free-radical have been associated in the pathology of several human diseases, including cancer, atherosclerosis, malaria, and rheumatoid arthritis and neurodegenerative diseases  (Aruoma, 1998). Mutations in mitochondrial DNA and oxidative stress both is a risk factor for neurodegenerative diseases, which contribute to ageing (Lin & Beal, 2006). Oxidative stress occur when the balance between the production of reactive oxygen species (ROS) and antioxidant defences disturbed (Kang, 2002). There are two types of oxygen free radicals, RNS (Reactive Nitrogen Species) and ROSs (Reactive Oxygen Species)(Turrens, 1997). There are two mechanism in biological system for the production of ROS i.e. enzymatic and non-enzymatic reaction. The difference between these reactions regulated by the oxygen concentration under oxygen deficiency stress (Blokhina, Virolainen, & Fagerstedt, 2003).Oxidative stress is responsible for frequent types of embryo damage. ROS can diffuse through cell membrane and change lipids, protein and nucleic acid. ROS induce mitochondrial dysfunction (Guérin, El Mouatassim, & Ménézo, 2001). DNA fragmentation increased because of ROS (Lopes, Jurisicova, Sun, & Casper, 1998). Sulphydryl oxidation and disulphide formation occur due to ROS. The disulphide bonds formation rate increase within the cell, as a result enzymes deactivate (Gutteridge & Halliwell, 1989). Mitochondrial DNA is vulnerable to mutation due to lack of histone which usually reduce ROS.  Oxidative stress increase the mutation of mitochondrial DNA four fold than nuclear DNA (Taanman, 1999).Antioxidants and their defence mechanism:An antioxidant is a substance that, considerably delays or inhibits oxidation of oxidizable substrate even when present at low concentrations compared to those of an oxidizable substrate (Halliwell, 1990). Natural antioxidants are obtained from herbs. Natural antioxidants are widely considered for their capability to protect organisms and cells from damage caused by oxygen reactive species. oxidative stress is  responsible for aging, degenerative disease and cancer (Cozzi et al., 1997). Carotenoids and vitamin C are extensively studied for the protection of DNA from oxidative free radical damage (Sies, Stahl, & Sundquist, 1992). Thymol is an effective and active antioxidant against lipid oxidation (Yanishlieva, Marinova, Gordon, & Raneva, 1999).