ABSTRACT
Coccinia grandis
Coccinia grandis (L.) Voigt is a commonly used anti-diabetic herb in the Sri Lankan traditional medicinal system. It is known as ‘kowakka’ in Sinhala and ‘Kovai’ or ‘Kwai’ in Tamil. The leaves are the commonly consumed part of the plant, and as a salad are eaten with rice and curry or with rice porridge. The phytochemicals of this plant include saponins, flavanoids, glycosides, xyloglucan, taraxerol, carotenoids, and cryptoxanthin. The flavonoids contribute to significant antioxidant properties, which have been observed in various solvent extracts of the leaves of the plant. The fruit is also consumed for anti-diabetic purposes, although mostly in other countries of the Indian sub-continent. C. grandis is not regulated for use, since the fresh plant is so widely available.
Costus speciosus
Costus speciosus is an important medicinal and ornamental plant used in the traditional medicinal system of Sri Lanka to cure different diseases. The plant primarily is useful as an anti-diabetic and in prevention of complications of this disease condition, as well as other medicinal properties associated within the traditional medicinal system of Sri Lanka. It possesses anti-inflammatory, anti-microbial, antioxidant, anti-dyslipidemic, and anti-cancer activities. Costus speciosus has become a popular form of anti-diabetic treatment in Sri Lanka in modern times and can be readily obtained cheaply from the marketplace. Diosgenin and eremanthin are the two major bioactive compounds, which have been tested in vitro and in vivo for a variety of therapeutic effects. However, if demand increases, mass production of C. speciosus may require biotechnological methods such as tissue culture and germplasm preservation.
Plectranthus amboinicus (Lour.) Spreng
P. amboinicus belongs to a genus where most plants under this category are cultivated for landscaping purposes. P. amboinicus emanates a pleasant flavor and odor that its leaves and essential oil are used for culinary purposes in Sri Lanka. The plant is known as ‘kapparawalliya’ in the vernacular language of Sinhala in Sri Lanka and is grown in many backyards for horticultural purposes rather than for medicinal value. The chopped leaves are also used as a substitute for sage (Salvia officinalis) in meat stuffing as shown in historical evidence obtained from ola leaf records in the country. In Sri Lanka, extracts of P. amboinicus have been primarily used for antibacterial effects and to prevent infections. Phytoconstituents include 3-methoxy genkwanin, crisimaritin, p-coumaric acid, caffeic acid, taxifolin, rosmarinic acid, apigenin, and 5-O-methyl-luteolin. In vitro and in vivo studies have shown antioxidant, anti-inflammatory, antibacterial, larvicidal, anti-arthritic, hepatoprotective, diuretic, and anti-diabetic effects of the herb. However, no clinical trials have been conducted to date.
Kalanchoe laciniata (L.) DC
K. laciniata is known as ‘Akkapāna’ in the vernacular language of Sinhala. Ethnobotanical surveys indicated that the plant has been used primarily for wound-healing effects as well as for disease conditions such as diabetes, jaundice, and rheumatism. However, its therapeutic properties appear to be based at present primarily upon such surveys, since there are few systematic studies elucidating the ability of the plant to prevent or cure disease conditions through in vitro, in vivo, or clinical means. Hellibrigenin-3-acetate is present in K. laciniata, but its therapeutic effects have not been properly elucidated. Importantly, Kalanchoe species contain cardiac glycosides, which have been observed to be toxic to animals.
Vitex negundo
Vitex negundo is an important herb in the traditional medicinal pharmacopoeia of Sri Lanka. It is called ‘Nika’ in the vernacular language of Sinhala. All parts of the plant, from root to fruit, possess a multitude of phytochemical secondary metabolites that impart an unprecedented variety of medicinal uses to the plant. The pharmacological potential of V. negundo has been exploited effectively in formulating several commercial products for treatment of health disorders, many of which are readily available especially in the consumer market of the Indian sub-continent. The bioactive compounds of negundin B and vitrofolal E were present in the leaf extract of the plant and demonstrated inhibitory activity against lipoxygenase and butyryl-cholinesterase, respectively, and f vitexicarpin, which shows cytotoxic activity.
Ocimum tenuiflorum
Ocimum tenuiflorum is commonly known as ‘Holy Basil’ in English and ‘Tulasi’ or ‘Tulsi’ in Sri Lanka. The plant is native to the Indian sub-continent and has a significant place in Hinduism for its rites and rituals. However, in Sri Lanka, the plant is mostly grown for horticultural and medicinal purposes. There appears to be several commercial products that contain extracts of O. tenuiflorum, some of which cater to anxiety and stress disorders. It is also used as a flavoring agent in several cuisines of Malaysia and Thailand. The essential oil from the plant appears to have a significant number of uses, owing to the presence of eugenol. Ethnobotanical studies indicate the usage of the herb primarily for skin diseases. In vitro and in vivo studies have demonstrated the antioxidant, anti-inflammatory, anti-fungal, and antimicrobial effects of the herb. A few clinical trials have demonstrated and verified the use of the herb for stress disorders.
Mimosa pudica
Mimosa pudica Linn. is commonly considered as a weed in many parts of the globe. However, in Sri Lanka, it is a plant mentioned in the Ayurvedic pharmacopoeia and has been used to treat a variety of ailments including dermatological conditions, snake and scorpion bites, and diabetes. Throughout the Indian sub-continent, the plant has a significant history of use for the treatment of various ailments. The most commonly used plant parts of M. pudica for medicinal purposes are the leaves and root, although the flowers, bark, and fruit may be occasionally used. Specifically, one current practice in Sri Lanka is the usage of the plant to bathe infants. The whole plant is boiled in water and the exudate is used. The extract offers protection from various dermatological defects that are already present or are expected to be contracted after birth. Several bioactive compound groups such as terpenoids, flavonoids, glycosides, alkaloids, quinines, phenols, tannins, saponins, and coumarins have been identified in various parts of the plant, which could be related to its multitude of therapeutic effects. Overall, M. pudica should not be simply recognized only as an invasive plant; it possesses a multitude of therapeutic effects presented herein.
