Persicaria minor

Persicaria minor is a herb species of the Polygonaceae family, with synonym Polygonum minus, and is also known by the common names small water-pepper, small smartweed, pygmy smartweed, spotted lady's thumb and kesum (Malay). This herb is native to Asia, but distributed widely in Europe and Australia. It is used in South East Asian cooking. Persicaria minor is native to South East Asia, including Malaysia, Thailand, Vietnam and Indonesia. It grows wild in cooler highlands, but is also found in wet lowland areas near rivers, ditches, and canals. It is a creeping plant with slender stems, and grows upright to a height of 1 to 1.5 meters. The creeping stem is green with reddish tinge, is cylindrical in shape, and has short nodes about 9 mm apart. Its leaves are long and narrowly-tapering, alternately arranged, and green with short, reddish petioles. Its flowers are minute, pale violet, and are 12 to 15 cm long. Persicaria minor is an edible herb. In Malaysia and Singapore, the shoots and young leaves are eaten raw as part of salad (ulam); used as an aroma spice additive in peppery dishes such as laksa, nasi kerabu, asam pedas and tom yam; used as tea leaves; and used for topical applications. Its oil has been used for aromatherapy and in treatments for dandruff. In Malaysian traditional medicine, P. minor has been used in post-natal tonics and for treatment of digestion. Pharmacological studies on P. minor have indicated anti-oxidant, LDL oxidation, anti-inflammatory and anti-microbial activities, digestive enhancing and anti-ulcer activities, as well as cognitive enhancing activities. Comparative studies have been carried out to analyse the metabolites not only in the plant's leaves, but also in its stem and roots.