There is horticultural confusion of Croton with Codiaeum, a small and distantly related Malesian genus of Euphorbiaceae whose common name “croton” refers to the worldwide cultivated ornamental varieties of Codiaeum variegatum (L.) A. Juss.
The genus Croton belongs to the flowering plant family Euphorbiaceae which include 313 genera and over 8100 species that are cosmopolitan in distribution. Croton is a “giant genus,” with 1223 species accepted in The World Checklist and Bibliography of Euphorbiaceae by Govaerts et al. (2000). But others put the number of species under Croton at 1797 starting with Croton abaitensis (1st species) and ending in Croton zeylanicus (1797th species). All the species under Croton are herbs, shrubs, trees and occasionally lianas (climbers) that are ecologically prominent and important elements of secondary vegetation in the tropics and subtropics worldwide (Webster, 1993; Govaerts et al., 2000).
Croton belongs to subfamily Crotonoideae, which is characterized by mostly lactiferous taxa having pollen with an unusual (crotonoid) exine pattern of triangular supratectal elements attached to a network of muri with short columellae (Nowicke, 1994 ). Most of the subfamily, including Croton, is also characterized by inaperturate pollen, which is an unusual condition in the angiosperms. The subfamily has been divided into as many as 12 tribes (Webster, 1975, 1994; Radcliffe-Smith, 2001).
From India more than 30 species of Croton have been reported so far. In Manipur 4 species of Croton i.e. Croton bonplandianus, Croton chlorocalyx (Manipuri name-Iton phaibi), Croton joufra and Croton roxburghii (Manipuri name-Thoungang) have already been described. The fifth species is the Miracle Plant of Saikot i.e., Croton caudatus Geisel. (Manipuri name-Yong Khullokpi and Khagi laikoi).
Croton is rich in secondary metabolites including alkaloids and terpenoids (Rizk, 1987), the latter including irritant co-carcinogenic phorbol esters (Phillipson, 1995). Some of the phytochemical present in different species of Croton includes 1-5% volatile oil including eugenol, vanillin, crotsparinine, crotoflorine, oblongi-foliol, triterpenic acid, sparciflorine, dotricontamol, b-amyrin and b-sitosterol. Some of the species may cause contact dermatitis (the phytochemical phorbol myristate is the most active skin irritant) while the seeds of others are supposed to promote tumours. Croton oil which is present in many of the species including Croton tiglium Linn., is one of the most purgative substances known, itself not tumour-inducing but when applied with a sub-effective carcinogen it is and may account for high level of oesophageal cancer in China (Croton flavens Linn., may do the same in West Indies). Diterpene resins found in many species of Croton have been used experimentally in studies of tumour initiation and conceivably prove to be useful in cancer therapy. Several species of Croton are used in traditional folk medicine throughout the world. The red sap of several South American species, known as “sangre de drago” or dragon’s blood, is used medicinally at the local level as well as in the international herbal supplements market (Meza, 1999). Thus presence of croton oil and phorbol myris-tate may be responsible for side effects like diarrhoea and skin allergy while using Croton species in traditional folk medicines.
In India only five species of Croton are used in ethnomedicine. The species are Croton bonplandianus Bail., Croton caudatus Geisel., Croton chlorocalyx Linn., Croton joufra Roxb., Croton roxburghii Balakr. and Croton tiglium Linn. These species are used in the treatment of various diseases, disorders and ailments like antifertility, boils, bowel complaints, chicken pox, cholera, cold and coughs, constipation, cuts and wounds, diarrhoea, dysentery, eye diseases, epilepsy, fever, gastric disorders, insanity, jaundice, liver complaints, malaria, rheumatism, ringworms, scurvy, spasmolytic agent, snake bite, sprains, etc. Recently the use of the powdered roots of Croton roxburghii Balakr (known as Hongkai in Arunachal Pradesh), in the treatment of cancer by the Khamti tribe of Arunachal Pradesh have been briefly reported.
The Miracle plant of Saikot:
The botanical name of the Miracle plant of Saikot is Croton caudatus Geisel. This species was first known to botanists in the year 1807 when it appeared in Croton Monograph. The plant is also known by different synonyms. In Indian flora, J.D. Hooker (1888) gave a very good description of the plant in his Flora of British India (volume V, page no. 388-389) along with its distribution and different varieties. From his description we can assume that this plant is known in India for the last one hundred years or so. Since then it appeared in different state and regional floras of India.
The generic name of the plant, Croton is derived from the Greek word ‘Kroton’ meaning a sheep tick which the seeds of this plant resemble whereas the specific name, caudatus is derived from the Latin word ‘caudum’ meaning ‘Tail like’ which the shape of the inflorescence resembles.
This plant is a straggling shrub. The leaves are extremely variable, the smaller ones being ovate-cordate and 2.5 to 7.5 centimeters long and the larger ones, orbicular-cordate and 10 to 18 centimeters long. The margin is coarsely toothed and often has a gland at the sinus or else in the teeth. The racemes are very long, slender, 10 to 18 centimeters long solitary and terminal. The male flowers are hairy, with sepals and petals of equal length. In the female the sepals are ovate or oblong and the petals are very minute, subulate and long ciliate. The fruit (capsule) is woody nearly spherical or broadly oblong, 2 to 2.5 centimeters long, terete or with 6 slender ridges, densely yellow-brown stellate-hispid. The seeds are unusually variable most often dorsally compressed and slightly rugose. Flowering may occur during May-August, fruiting during July-October.
Croton caudatus Geisel seems to have some varieties like C. caudatus var. harmandii Gagnepain; C. caudatus var. malaccanus J. D. Hooker; C. caudatus var. hispida; C. caudatus var. ruminata; C. caudatus var. globosa and C. caudatus var. tomentosa.
In India the plant is reported from the north eastern states like Assam, Meghalaya, Arunachal Pradesh and Sikkim. It is also reported from Western Ghats, West Bengal and Orissa. It is a new record for the state of Manipur and grows wild in Saikot area of Churachandpur District and Jiribam sub-division of Imphal East District.
It is also reported from Southern China (SW Yunnan) and southward to Sumatra, Java, Christmas Islands, Borneo, Philippines, Bangladesh, Bhutan, Brunei, Cambodia, Laos, Malaysia, Myanmar, Nepal, Pakistan, Philippines, Thailand, Singapore, Sri Lanka, Vietnam and North Australia.
In the Philippines the plant is known as Alimpai. In Malaysia it is known as Tapasan Komudi. In China the plant is probably known as luan ye ba dou. In India this plant is known by different names in different dialects or local languages. In Assamese it is known as Ghahe-lewa; Sawaka in Garo; Kum-kumarong in Karbi; Soh-lambrang in Khasi; Matau in Lushai. It is also known by the names of Sonaphula and Tilaker-rik in other Indian dialects. In the Jiribam sub-division of Manipur the plant is known by the Manipuri names Yong Khullokpi and Khagi laikoi. In Saikot area of Churachandpur District, Manipur the plant is known as Ranlung Damdawi or Chawilien Damdawi in Hmar language.
The plant is used in traditional folk medicine mainly in South East Asia. It also forms an important part of Dai medicine in China. In Malaysia root is boiled and the infusion to treat weak body and to avoid diseases. In the Western Ghats region of India the leaves and root of this plant is applied as poultice in sprains, as diuretic and in malaria. Kirtikar and Basu, Chopra and Caius state that the leaves are applied as a poultice to sprains. Burkill and Haniff report that the leaves may be used for poulticing during fevers. Burkill and Haniff continue that a decoction of the root causes purging and so it is administered for constipation; and, as purging may help fevers, it is used for them also. Colds are similarly treated. In Lakhimpur the young leaf buds are powdered with the leaves Caesalpinia sappan and used for liver diseases. In the Chandrapur area of Kamrup, Assam the plant is known as Bonmahudi and the barks and roots are used as antidysentric and in relieving pains. In Tirap District of Arunachal Pradesh, the leaves are used in liver complaints and the poultice in trauma and injury. In the Subansiri District of Arunachal Pradesh, the decoction of the leaves and roots are used in cold and cough. In the Balphakram Wild Life Sanctuary area of Meghalaya (Garo Hills), the decoction of the roots is used in malaria. In the Totopara and Jalpaiguri areas of West Bengal, the leaf is used in sprains. In the Jiribam sub-division of Manipur the Meitei community used the plant in the treatment of ringworms. It is also used in treating wounds of cattle. However the use of this plant in the treatment of cancer in the Saikot area of Manipur is a new record in the world of ethnobotany in general and ethnomedicine in particular.
Proper identification of any medicinal plant is of prime importance in ethnomedicine as any two species under the same genus may not give the same result. In China Croton caudatus is an important species in Dai folk medicine. Some other Croton species, in particular, C. kongensis, C. cascarilloides, C. crassifolius, C. lachnocarpus and C. olivaceus are often marketed as C. caudatus, and thus, the therapeutic effects of C. caudatus are not achieved. The respective morphological features of the plants are similar, and they are not easy to distinguish morphologically from each other. Besides this plant also have some varieties which are morphologically very similar to one another.
Thus in China in an attempt to find a method for discriminating among these species, their nuclear ribosomal DNA internal transcribed spacer (ITS) region are compared by the researchers at the College of Life Science, Sichuan University, Chengdu, Sichuan, People’s Republic of China. In this method species-specific probes were derived from the ITS region of these species for species identification. According to them this method provides effective and accurate identification of C. caudatus Geisel. Similarly Researchers at the University of Wisconsin–Madison and Smithsonian Institution (USA) the ITS and TRNL-TRNF DNA sequence data1 method is employed to determine the molecular phylogenetics of the giant genus Croton and tribe Crotoneae (Euphorbiaceae).
Thus it is the right time to establish the true identity of this very interesting plant species using the above mentioned techniques or any other suitable technique at some reputed research laboratory in India instead of depending upon the gross morphological characters alone. Books published on the flora and medicinal plants of Manipur used different botanical names for the same plant or the synonyms of the same plant are used for different plants found in Manipur.
**The writer is working as Reader in Botany at Thoubal College, Thoubal-795138 and can be contacted at firstname.lastname@example.org
The Sangai Express