Ethnobotanical, Phytochemical and Pharmacological Potential of Cycas revoluta Thunb-A review

Cycas revoluta Thunb. is a gymnosperm belonging to the family Cycadaceae. Sago Cycas, Sago Palm Sotetsu Nut, False Sago,1 Sago Palm of Japan and king sago palm2 are some common name of this species. Cycads have long been known to cause toxicity.3 Sago starch requires appropriate processing to eliminate its toxin before use otherwise, it can lead liver damage, vomiting and even death.4 In geological time scale, Mesozoic era was the golden period of this plant group.5 Many rare and endangered species are present in Cycadacece family.6 It is endemic to Japan but originally came from Southeast Asia. At present it is bounded to warm climate that previously found worldwide.7 It is a xerophytic plant.4 Sago palm is broadly distributed from southern Kyushu to Iriomotejima Island throughout the Ryukyu Islands on the rocky coast.5,8 C. revoluta population size is large in several regions.9 C. revoluta is widely cultivated trees, occurred in subtropical, tropical and temperate regions.10 It is a cycad that easily affected by water logging but can tolerate the drought and frost.1 It has a capacity to fix nitrogen in loamy (medium), sandy (light) and welldrained soil. It can grow in basic, neutral and acid soil.7 The name of this species of cycads is Cycas revoluta because of its revolving margin of leaflet. It is very good specimen as bonsai.4


INTRODUCTION
Cycas revoluta Thunb. is a gymnosperm belonging to the family Cycadaceae. Sago Cycas, Sago Palm Sotetsu Nut, False Sago, 1 Sago Palm of Japan and king sago palm 2 are some common name of this species. Cycads have long been known to cause toxicity. 3 Sago starch requires appropriate processing to eliminate its toxin before use otherwise, it can lead liver damage, vomiting and even death. 4 In geological time scale, Mesozoic era was the golden period of this plant group. 5 Many rare and endangered species are present in Cycadacece family. 6 It is endemic to Japan but originally came from Southeast Asia. At present it is bounded to warm climate that previously found worldwide. 7 It is a xerophytic plant. 4 Sago palm is broadly distributed from southern Kyushu to Iriomotejima Island throughout the Ryukyu Islands on the rocky coast. 5,8 C. revoluta population size is large in several regions. 9 C. revoluta is widely cultivated trees, occurred in subtropical, tropical and temperate regions. 10 It is a cycad that easily affected by water logging but can tolerate the drought and frost. 1 It has a capacity to fix nitrogen in loamy (medium), sandy (light) and well-drained soil. It can grow in basic, neutral and acid soil. 7 The name of this species of cycads is Cycas revoluta because of its revolving margin of leaflet. It is very good specimen as bonsai. 4 It has several medicinal properties so its different parts are used to treat many diseases like estrogen dependent carcinoma, cancer, hepatoma, diarrhea and dysentery, flatulence, vomiting, piles and wound. C. revoluta is the utmost famous ornamentals among the cycads. In the Philippines and Indonesia, Cycads leaves are used as a vegetable and root nodules of C. revoluta which are edible and have been reported as a 'potato-like' substance. 11,3 Starch grains that are obtained by its pith and cortical cells of stem are used by the poor people and people of hilly area in starvation condition. Seeds and pulps (removed basal offsets) are used to propagate this species. 12 In this review the present authors tried to compile all the informations related to its taxonomy, ethnobotanical uses, phytochemistry and pharmacological uses comprehensively to explore the utility of C. revoluta.

TAXONOMIC DESCRIPTION
Cycas revulata is a palm-liked evergreen, slowgrowing, medium sized, perennial, branched with multiple heads, 4 woody, 13 0.5-2 m tall 14 and 35-95 cm wide trunked dioecious tree which has a lifespan of more than 100 years. 15 Stem of young age tree is tuberous while old tree has thick columnar and rough stem. 4 Glossy green, thick, many, populous, large pinnately compound and 0.5 to 1.5m long leaves are found in it that have more than 100 linear leaflets with downward rolled margins and sunken midrib. 16 Veins are absent in midrib. Main rachis is curled in young leaves. It bears both scaly and foliage leaves which are arranged in alternative manner. Scaly leaves are persistent and brown in colour and foliage leaves are pinnately compound and large with 60 cm length. Scaly leaves existing in more quantity than foliage leaves and play a role in the protection. Leaves have quadrangular and thicked petiole. 4 Leaves are produced by the plant throughout the year and last for many years. 14 The flowers of C. revoluta are dioecious it means that both female and male flowers are on different plants and an individual plant has either female flower or male flower. Flowering begins in May and ends in July. 7 Male cones are characterized by sporophylls, narrowly ovoid to cylindrical, hairy, brown in color and a short up curved point with narrowly wedge shaped whereas loose, open, hairy, brown, densely brown hairs on sporophylls, apical lobe ovate, deeply laciniate margin with 12-18 tapered lobes characters are present in female cone. 1 Cycas revoluta has anemophily and entomophily both type of pollination. 14 A red coated approximately 3cm wide and 4 cm long and seeds are produced by C. revoluta. 8 Normally seeds of cycads are heavy in weight that's why they sink in water. Seeds of C. revoluta show very low percentage of germination. 12

ETHNOBOTANICAL POTENTIAL OF CYCAS REVOLUTA
C. revoluta is very important ethnobotanical plant for the local people of hilly areas because it is used by them as medicinal and non medicinal purposes. It contains starch in a very good quantity so it is used as a food by different ways such as sago, flour, bread, cake, vegetables etc. Its different plant parts are also used to household needs and to treat many diseases. Household needs include funeral wreaths, decoration and the making of huts, ropes, cloths, brooms, baskets from plant parts ( Table 1).

PHYTOCHEMICAL CONSTITUENTS OF CYCAS REVOLUTA
Many types of phytoconstituents have been extracted and isolated from different solvents of various plant parts of C. revoluta. The potent phytochemicals are lectins, flavonoids, lipids, chitinase, estragole, glycoside, nonprotein amino acid and essential oil. NaCl/Pi, chloroform, ethyl acetate, methanol, diethyl ether, petroleum ether, and ethanol are some solvents which have been used for extraction ( Table 2).

PHARMACOLOGICAL ACTIVITIES OF CYCAS REVOLUTA
Researchers have been reported many kinds of pharmacological activities in C. revoluta like antiviral, astringent diuretic, antioxidant, antidiabetic, antimicrobial, antibacterial, antileishmanial activity, antifungal, cytotoxic, anticancer, antirheumatic. The detailed pharmacological activities are tabulated in Table 3.