Background

Trinidad and Tobago is one country consisting of two adjacent islands located just northeast of the Venezuelan coast with a combined area of 5070 km2 [1]. The human population of 1.25 million is multi-ethnic, multi-religious and multicultural and increases at 1% annually. In Trinidad, the major population centres are concentrated along the west coast and along an east-west transportation corridor in the north of the island [1].

The multi-ethnic population of Trinidad and Tobago is reflected in its folk medicinal use. Previous research has indicated that the folk medicines used by hunters are derived from ancient Amerindian practices [2]. This paper will continue to explore the cultural origins of Caribbean folk medicine by investigating the contribution of the Chinese to Caribbean folk medicine. Chinese medicine has been described as a complex and holistic system of medical practice with its own philosophy, diagnosis, treatment systems and pharmacology which also includes acupuncture, moxibustion and Qi Gong. However in this paper I will focus on 'Ben Cao' (Herbalism) [3].

The Chinese were the first Asian immigrants, arriving before the original East Indians who arrived in 1845. Chinese Tartars (192 men and one woman) were brought to Trinidad in the fall of 1806. These men from Macao, Penang and Canton were brought to cultivate tea but most were dissatisfied with local conditions and returned on the same ship [4, 5]. The twenty-three who stayed made a living as entrepreneurs (butchers, shopkeepers, carpenters and market gardeners) and creolised (integrated into the local population).

Prominent sugarcane planters believed that the emancipation of Caribbean slaves in 1838 would create a labour shortage. In the 1840s, the British "opened" a labor market of displaced or impoverished peasantry in southern China to fill this shortage and 2,500 mainly-male Chinese were brought legitimately to Trinidad as indentured workers, or were 'shanghaied' (abducted by European traders) [6]. After the first Opium War (1840–42), and second Opium War, the British (as well as French and Americans) occupied twelve major ports (and colonized Hong Kong) [6]. China's defeats in the Opium Wars led to the deregulation of Chinese immigration. This combined with the unrest, rebellion, and war in China, facilitated the organized labour traffic of one million southern Chinese to the West from 1840 to 1875 [6].

Three vessels brought 1,100 Chinese indentured labourers to Trinidad in 1853 and 600 more came in 1865 and 1866. In 1862, 467 immigrants came from Hong Kong. Most of the immigrants arriving between1853 and 1866 came from the southern Guangdongprovince (Macao, Hong Kong and Canton). In the last 5 trips, a total of 2837 emigrants came from Macao, Amoy, Canton and Hong Kong. Chinese migration after 1911wasdriven by the Chinese revolution. Punti traders described Hakka prisoners as pigs on the bills of lading and shipped them to the Caribbean and South America [4, 5]. Between 1920s and 1940s new immigrantsconsisted of the families and friends of earlier migrants. They came as merchants, peddlers, traders and shopkeepers, not indentured labour [4]. Almost 9,000 more Chinese immigrants came voluntarily from British Guyana to Trinidad over the next century, after having served their indentureship [5]. Chinese people now constitute approximately 1% of the Trinidad and Tobago population as an ethnic group but are also present in the large mixed-raced population of 18 – 25%.

There is one publication that describes the use of medicinal plants by the Chinese community in Trinidad [7]; it contained no plants in common with those in this research [1]. Nevertheless in the discussion section of this paper, comparisons will be made of the uses of the plants in Trinidad and Tobago and those current in Asia and South-east Asia. The ethnomedicinal literature available from Asia will be used in the non-experimental validation.

Fifty-eight plants used in ethnomedicine in Trinidad and Tobago for skin problems, stomach problems, pain and internal parasites are described in this paper and a non-experimental validation of them is presented. The recent publication of high-quality studies and clinical trials on the ethnomedicinal plants in this paper has enhanced the non-experimental validation of the plants presented in the discussion section.

Methods

Study design

This study adhered to the research guidelines and ethical protocols of Wageningen University in the Netherlands. Thirty respondents, ten of whom were male were interviewed from September 1996 to September 2000. The respondents were obtained by snowball sampling, and were found in thirteen different sites, 12 in Trinidad and one in Tobago. Snowball sampling was used because there was no other means of identifying respondents. The chief objective of the sampling method was to identify knowledgeable respondents.

Twenty respondents were interviewed once, the other ten (who were healers) were interviewed three or four times. Healers were also asked to reconstruct the circumstances and contexts of the plant uses so that the means of administration of the plants could be identified. No interview schedule of questions was used but a more qualitative, conversational technique. Plants were collected when available to verify that the common names used by each respondent were the same in each ethnic group as those recorded in the literature. The majority of the plants were identified at the Herbarium of the University of the West Indies but voucher samples were not deposited. This ethnomedicinal study was part of a larger research project on ethnoveterinary medicine; other data collecting techniques were used in the larger study [1].

Non-experimental validation

The ethnomedicinal plants used in Trinidad and Tobago for skin problems, stomach problems, pain and internal parasites are presented in Tables 1 and 2.

Table 1 Ethnomedicinal plants used for skin problems in Trinidad and Tobago
Table 2 Plants used for stomach problems, pain and internal parasites in Trinidad and Tobago

The plant-based remedies were evaluated for safety and efficacy with a non-experimental method. Published sources such as journal articles and books and databases on pharmacology and ethnomedicine available on the Internet were searched to identify the plants' chemical compounds and clinically tested physiological effects. This data was incorporated with data on the reported folk uses, and their preparation and administration in Latin America, the Caribbean, Asia and Africa. For each species or genus the ethnomedicinal uses in other countries are given if available; then follows a summary of chemical constituents, in addition to active compounds if relevant (Tables 3 and 4). This type of ethnopharmacological review and evaluation has been previously published [2]. The plant uses in China are then given (Table 5) and a comparison of the uses in Trinidad and China is made in the discussion.

Table 3 Non-experimental validation of plants used for skin problems in Trinidad and Tobago
Table 4 Non-experimental validation of plants used for stomach problems, pain and internal parasites in Trinidad and Tobago
Table 5 Chinese ethnomedicinal uses for the Chinese-origin plants or closely related species used in Trinidad

Results

The ethnomedicinal plants used in Trinidad and Tobago for skin problems, stomach problems, pain and internal parasites are presented in Tables 1 and 2.

Plants used for skin problems

Twelve plants are used for skin problems including one for the rash caused by measles plus one for shingles. The majority of the plants were being used for children including babies. The thirteen plants belong to nine plant families. Eight plants are used to bathe babies. Acnistus arborescens Croton gossypifolius and Manihot esculenta are used to bathe babies for eczema. Bidens alba/Bidens pilosa and Origanum vulgare are used to bathe babies and older children. Eclipta prostrata is combined with a non-plant material and used to bathe children for malnutrition. Solanum americanum is also used to bathe children for malnutrition.Azadirachta indica and Chamaesyce hirta/hypericifolia are used for measles. Sida carpinifolia (syn. Sida acuta) and Spondias mombiin are used for eczema. Achyranthes indica, Cassia alata and Chamaesyce hirta/hypericifolia are used for skin rashes and other skin problems.

Plants used for stomach problems, pain, internal parasites

The medicinal plants used for stomach problems, injuries, endoparasites, arthritis and bites are combined in Table 2. This grouping partially reflects the analgesic activity of many of the plants used. Eighteen plants are used for stomach problems including diarrhoea. Another fifteen plants are used for various kinds of pain including cuts, bites, sprains and arthritis. Four plants are used as anthelmintics. Other plants in the table are used for dropsy. Twenty-seven plant families are represented in Table 2.

The following plants are used as carminatives: Cecropia peltata,Aframomum melegueta,Ferula asafoetida and Tournefortia hirsutissima.

The following plants are used for stomach problems: Ambrosia cumanenesis, Aristolochia rugosa/trilobata, Capraria biflora, Dorstenia contrajerva, Cajanus cajan, Momordica charantia,Punica granatum, Brownea latifolia and Cocos nucifera.

Diarrhoea is treated with the following plants: Chamaesyce hirta, Eleusine indica, Peperomia rotundifolia, Phyllanthus urinaria and Scoparia dulcis.

The plants used as anthelmintics are Citharexylum spinosum, Cucurbita maxima, Portulaca oleraceae,Tagetes patula and Eupatorium triplinerve.

Plants used specifically for pain are: Brownea latifolia,Abelmoschus moschatus, Eupatorium macrophyllum, Morinda citrifolia and Cola nitida.

Arthritis is treated with the following plants: Nicotiana tabacum, Petiveria alliacea, Rosmarinus officinalis and Neurolaena lobata.

Plants used for cuts, injuries and swellings are: Solanum melongena, Jatropha curcas/gossypifolia, Bidens alba/Bidens pilosa, Cucurbita pepo, Tournefortia hirsutissima, Bambusa vulgaris, Bixa orellana and Cocos nucifera.

Scorpion and snake bites are treated with Tamarindus indica, Nopalea cochinellifera, Centropogon cornutus and Rosmarinus officinalis.

Non-experimental validation of plants used for skin problems in Trinidad and Tobago

For each species or genus the ethnomedicinal uses in other countries, particularly Asian countries, are given if available; then follows a summary of chemical constituents, in addition to active compounds if relevant to the condition being treated (Tables 3 and 4).

Comparative evaluation of plants used for skin problems, stomach problems, pain and internal parasites

Table 5 contains a preliminary listing of the ethnomedicinal plants discussed in this paper that are used similarly in Chinese ethnomedicine. If the specific plant was not found in the literature search the closely related species that are used similarly in Chinese traditional medicine are listed.

The commonalities between Chinese traditional medicine and Trinidad and Tobago "bush medicine" are provided below.

Abelmoschus moschatus is used to treat depression and anxiety in traditional Chinese medicine [94]. In Trinidad and Tobago it is used for pain.

Achyranthes bidentata ("Niu Xi" in Chinese medicine, Radix Achyranthes Bidentatae) is used as a tonic, to nourish the liver and kidneys, and invigorate circulation [95].Achyranthes indica is used in Trinidad and Tobago for skin rashes and other skin problems.

Aristolochia manshuriensis (AMA, "Guanmuton") is used in China as a diuretic and anti-inflammatory [96]. Aristolochia rugosa/trilobata are used in Trinidad and Tobago for stomach problems. Zhu claims that the Chinese herb "Mu Tong" has been based on Aristolochia manshuriensis only since the 1950s. The classical Chinese herbal literature until the mid 17th century identifies "Mu Tong" as several Akebia species and no toxicity related to "Mu Tong" was recorded in these traditional Chinese herbal texts.

Bidens parviflora ("Xiaohua-Guizhencao") is used as a traditional antipyretic, anti-inflammatory and anti-rheumatic medicine in China [97]. Plants used for cuts, injuries and swellings in Trinidad and Tobago include Bidens alba/Bidens pilosa.

During the ethnomedicinal research one of the respondents claimed that the use of Cajanus cajan for internal parasites was a recent addition to Trinidad folk medicine. This ethnomedicinal practice in Trinidad is the same as that reported for the folk medicine of China (to kill parasites) [98] but no definitive statements about its origins can be made at this time. Momordica charantia seeds or "Ku guazi" are used for infections and immune disorders [103]; in Trinidad and Tobago the plant is used for stomach problems.

"BaJiTian" (Morinda officinalis) has been prescribed in China for about two thousand years, for tonifying the kidney, strengthening "Yang-qi" and relieving rheumatism [104]. Plants used for pain in Trinidad and Tobago include Morinda citrifolia.

Phyllanthus urinaria is extensively grown in China. It is used to treat jaundice, hepatitis B, neprolithiasis, and painful disorders [106]. Diarrhoea is treated with Phyllanthus urinaria in Trinidad and Tobago.

Portulaca oleracea ("Ma-Chi-Xian") is grown widely in China, and is used traditionally for alleviating pain and swelling [106]. It is used as an anthelmintic in Trinidad and Tobago.Tamarindus indica fruit is used as a blood tonic and the seed coat of Tamarindus indica is used to treat burns and aid in wound healing in China. In Trinidad and Tobago, scorpion and snake bites are treated with Tamarindus indica.

Discussion and conclusion

Vincent Yáñes, the captain of the caravel Niña reportedly dug up Morinda citrifolia in Hispaniola on December 30, 1492 [1]; yet this plant was not considered special in Trinidad until the forces of globalisation made "Noni" ubiquitous as an "Australasian cure-all" and it was then sold on the streets of Trinidad by herbalists and other traders [1]. This story illustrates that since Caribbean folk medicine is a product of globalisation and colonisation, research into its origins and plant uses is complex. Attributing specific uses to Chinese folk medicine would necessitate access to the earliest Chinese herbals.

The ship that brought 467 Chinese men, women, and children (from an original 549) in 1862 was the first ship to bring Chinese women to Trinidad. In the last 5 voyages (1862–1866), of 367 females embarked, 309 landed. The immigrant gender imbalance may have affected the dissemination of Chinese folk medicine into the Caribbean culture. Two wars taking place in eastern China in 1862 facilitated the immigration or abduction of Hakka peoples to the Americas and presumably the Punti peoples came in the later stages of immigration [108, 109]. If any of these original immigrants had expertise in Chinese plants, besides knowledge of opium, they did not widely advertise this under the British colonial administration.

It may be the case that the Chinese contribution to Caribbean folk medicine has formed part of its earliest foundation and its provenance is not remembered. Research on the Chinese contribution to Trinidad is complicated by the fact that many of the Hakka research population have lived up to their migratory reputation – moving on to North America. Language is also a barrier.

Cuba and other Caribbean countries have not adopted the model of China's barefoot doctors. Cuba's medical diplomacy and investment in biotechnology generates symbolic capital: intangible qualities (like honour, prestige, and reputation) which appear opposed to strictly economic interests, are in fact convertible back into material capital [110]. The Cuban policy is to demonstrate that its socialist state can provide a modern health care system and need not settle for small-scale technologies like traditional medicine [110]. In contrast it has been estimated that 80% of medications used in Chinese rural areas are derived from Chinese materia medica and related products. These products are economical and therefore provide important cost savings [2, 111, 112].

Similarly to the process taking place in the Caribbean, younger people in Taiwan have been moving away from Chinese medicines because work pressures force them to seek faster cures from allopathic doctors [2]. However tonic herbs such as "Danggui" (Radix Angelica sinensis), "Huangqi" (Radix Astragali/Astragalus membranaceus), "Gou Qi Zi" (Fructus barbarum) and "Renshen" (Radix Panax ginseng /Panax notoginseng), are used by Taiwanese families in slow-cooking winter meals. These herbs are also popular for postnatal care, for the eldely and for postsurgical therapy [2].

Non-experimental validation is a new approach that is designed to introduce cost effectiveness into medicinal plant research. The findings of the non-experimental validation suggest that the majority of the therapeutic applications of the plants used in Caribbean folk medicine listed in this paper are justified, and more studies are warranted to explore their efficacy. All of the plants used in Trinidad and Tobago for skin problems merit clinical trials. The plants used for stomach problems, pain and internal parasites that should take priority in clinical trials are Bambusa vulgaris, Bidens alba, Jatropha curcas, Neurolaena lobata, Peperomia rotundifolia and Phyllanthus urinaria.