Non-experimental validation of ethnoveterinary plants ... - Springer Link

Trop Anim Health Prod (2007) 39:375–385 DOI 10.1007/s11250-007-9026-0

ORIGINAL ARTICLE

Non-experimental validation of ethnoveterinary plants and indigenous knowledge used for backyard pigs and chickens in Trinidad and Tobago C. Lans & K. Georges & G. Brown

Accepted: 24 April 2007 / Published online: 3 July 2007 # Springer Science + Business Media B.V. 2007

Abstract This paper presents the findings of an exploratory study on ethnoveterinary medicines used for backyard pigs and backyard chickens in Trinidad and Tobago. Research data was collected from 1995 to September 2000. Six plants are used for backyard pigs. Crushed leaves of immortelle (Erythrina pallida, E. micropteryx) are used to remove dead piglets from the uterus. Leaf decoctions of bois canôt (Cecropia peltata) and bamboo (Bambusa vulgaris) are used for labour pains or leaves are fed as a postpartum cleanser. Boiled green papaya fruit (Carica papaya) is fed to pigs to induce milk let-down. The leaves and flowers of male papaya plants (Carica papaya) are fed to deworm pigs. Sour orange juice (Citrus aurantium) is given to pigs to produce lean meat, and coffee grounds are used for scours. Eyebright and plantain leaves (Plantago major) are used for eye injuries of backyard chickens. Worm grass (Chenopodium ambrosioides) and cotton bush (Gossypium species) are used as anthelmintics. Aloe gel (Aloe vera) is used for internal injuries and the yellow sap from the cut Aloe vera leaf C. Lans (*) BCICS, University of Victoria, Victoria, BC V8W 3R4, Canada e-mail: [email protected] K. Georges : G. Brown School of Veterinary Medicine, Faculty of Medical Sciences, The University of the West Indies, St. Augustine, Trinidad and Tobago

or the juice of Citrus limonia is used to purge the birds. A literature review revealed few toxicity concerns and the potential usefulness of the plants. Keywords Ethnoveterinary medicine . Trinidad and Tobago . Backyard chickens . Backyard pigs Abbreviations IMF International Monetary Fund i.p. intraperitoneal p.o. per os TTD Trinidad and Tobago dollar

Introduction This paper presents the findings of an exploratory study on medicinal plants used for backyard pigs and backyard chickens and a non-experimental validation of these plants. Family poultry (which are kept as small flocks of free-ranging birds owned and cared for primarily by women and children) and pigs provide a critical source of food and income for people in developing countries. Although shelter and supplemental food may be provided, there is little economic input, making it possible for the majority of rural families to keep poultry and a few pigs (Guèye, 1997; Lans et al., 2007). This study was part of a

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larger research project on ethnoveterinary medicines used in Trinidad and Tobago (Lans, 2001). The number of users, type of users of the plants or consistency of use can be a guide to their merit. However, in this paper a non-experimental validation of the plants, based on a methodology developed by Browner and colleagues (1988) and Heinrich and colleagues (1992) is used as a guide to the likely safety and efficacy of the plants. International scholars have recently recognized evaluation in ethnoveterinary research (Diehl et al., 2004). Traditional validation is very costly. It is claimed that only drug companies with sales of USD 5 billion can engage in drug discovery. One factor leading to high costs is that sometimes multiple plant mixtures are used. There are complex chemical interactions among constituents of a single plant and with mixtures of plants. Other considerations are whether mixing some plants together increases the availability of bioactive compounds, or whether preparations diminish toxicity while retaining therapeutic actions. Plant screening against microorganisms does not always evaluate a plant on its actual use (Lans and Brown, 1998).

Materials and methods Study area Trinidad and Tobago is a twin-island republic totalling 5123 km2. The terrain of both islands comprises low mountain ranges, lowlands and wetlands. The rainy season lasts from June to December. The population is currently estimated at 1.23 million and is mainly of African and East Indian origin with a small population of the original Amerindian and European inhabitants. 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. Agriculture and especially the livestock industry are marginalized because the economy is dominated by the petroleum industry, which contributes 50% of the government’s foreign exchange earnings and nearly 28% of government revenues (Harrison, 1994). Data collection The methodologies for data collection on backyard chickens and on backyard pigs were different owing

Trop Anim Health Prod (2007) 39:375–385

to certain differences in their prevalence and rearing. Backyard chickens are a specific kind of bird, typically male, that are kept by a select group of men and are kept until death. Flock sizes range from 5 to 500. A variety of people (men and women) raise backyard pigs all over the country with various standards of husbandry and housing. Small numbers of pigs are kept and these are raised and slaughtered for festive occasions. The data collection on medicinal plants used for backyard chickens was conducted from July to September 2000. A veterinarian who had clients with backyard chickens was contacted and he provided the names and phone numbers of six owner/trainers. Telephone contact was made with those individuals, but only one knew about plants other than aloes (Aloe vera) and worm grass (Chenopodium ambrosioides). During these interviews the plants and their uses were described by the owner and the birds were displayed. Besides the veterinarian mentioned above, no other medically trained personnel were interviewed for this study. Information on pigs was collected indirectly throughout the research period (1995–2000). Snowball sampling was used to generate a purposive sample of respondents who used ethnomedicines (Atkinson and Flint, 2001). Snowball sampling is part of link-tracing methodologies which take advantage of the social networks of identified respondents to provide a researcher with an ever-expanding set of potential contacts. Snowball sampling offers advantages if the aim of a study is primarily explorative, qualitative and descriptive and there is no intention to generalize the results to the wider population. Snowball sampling is used most frequently to conduct qualitative research, primarily through interviews. Secondly, snowball sampling is used as a more formal methodology for making inferences about a population of individuals who have been difficult to enumerate through the use of such methods as household surveys (Nalven, 1987; Etkin, 1993; Atkinson and Flint, 2001). The 30 respondents (including 10 men) in the purposive sample were interviewed from July 1995 to September 2000. The interviews were semi-structured, meaning that respondents were guided to speak on a wide range of issues associated with ethnomedicines, and described the uses of many plants. The data obtained from these interviews included information


on ethnoveterinary medicines used for pigs. The respondents were found in 13 different locations, 12 in Trinidad and one in Tobago. The majority of the interviews took place at the homes of the respondents; none took place on pig farms. Those respondents with pigs (8 of the 30) had raised one pig in their backyards to be slaughtered at Christmas time and had many years of experience. Additional information on pigs came from two members of a group of 7 hunters. These two men were long-term pig keepers and the opportunity was taken to interview them on ethnoveterinary medicines used for pigs during participant observation (five hunts over three years) with this hunting group. The total number of respondents with ethnoveterinary knowledge for pigs was thus 10. The explanation for these methods used for the research on pigs follows. In 1997, the number of pig farms was estimated at 262, a reduction from 527 in the 1980s (CSO, 1997). In 1995, the Agricultural Development Bank (ADB) and a national commercial bank sold 2500 nonperforming agricultural loans (worth more than TTD 300 million) to a newly created State enterprise. These loans were sold for 35 cents on every dollar of debt; and the 2308 pig and poultry farmers concerned were not told beforehand (Trinidad Express Newspaper February 28, 1998). Concurrently the major meat processors were not providing any concessions. Small-scale Tobago pig farmers had already been put out of business in the 1990s. In the 1970s and 1980s, pig farmers in Tobago sold their animals to a state-owned marketing agency. This agency suffered financial constraints during the IMF structural adjustment of the late 1980s and could not pay farmers for the meat supplied. Equipment failures at the agency led to the meat being discarded, forcing farmers to engage in other economic activities. Outbreaks of Brucella abortus infection and rabies in Trinidad in 1997, in combination with the political climate in agriculture, created a negative climate for conducting on-farm research. A decision was therefore made to focus on backyard pigs and to use snowball sampling to find the owners of these pigs. Specimens of the plants were not collected. The majority of the plants are common and not likely to be mistaken; eyebright could not be obtained. Notes taken during the interviews were transcribed within hours of each interview. The use, dosage (if provided), and name of respondent were catalogued with the previous entries for each plant. All of the respondents had used the plants

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they described, none of the information was secondhand, but they declined to give the frequency of use. In one case the respondent no longer kept backyard chickens and stated that his use of the medicinal plants was past use. The pharmacological and ethnomedicinal literature was searched manually and by computer to identify the plants’ chemical compounds and clinically tested physiological effects. Results Eight plants and/or products were used for medicinal purposes by backyard chicken owners. One of these plants (gru gru boeuf) was tentatively identified from the literature, but eyebright has not yet been identified. Six plants were used for backyard pigs. The plants used for backyard pigs and backyard chickens in Trinidad and Tobago are presented alphabetically by botanical name in Table 1. The plant uses are grouped into categories below. Respiratory problems All the respondents used a combination of honey and sour orange or lemon (Citrus species) to treat upper respiratory problems in backyard chickens. De-worming Worm grass (Chenopodium ambrosioides) was used by all the respondents in the wet season, but in the dry season anthelmintics (developed for humans and dogs) were used for convenience. Most respondents gave the birds an undiluted infusion of C. ambrosioides to drink and claimed to have no fixed dose. One respondent combined the worm grass with Epsom salts and soft candle (whale oil). The ingredients were mixed and made into a little ball and pushed down the throat of the bird. The worm grass infusion or anthelmintic was given when the respondents saw worms in the faeces or brown-coloured stool. Three respondents gave a decoction of Gossypium species to backyard chickens as the drinking water. Caution about dosage (six plant-tops with young leaves for ten birds) was expressed. One person said that overdosing with Gossypium species is dangerous. The yellow sap under the green epidermis of the Aloe vera leaf was used to purge birds after de-worming by four respondents. Two respondents removed the green

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two respondents. Two respondents used crushed leaves of immortelle (Erythrina pallida, E. micropteryx) in the drinking water to remove dead piglets from the uterus.

skin from the Aloe vera leaf, two merely cut off the end to collect the sap. All respondents purged birds with salt (sodium chloride), lemon juice or raw egg whites. Additionally one owner with a large flock of 300 birds gave aloes (Aloe vera) in the drinking water to the birds if they were likely to incur injuries from other birds. This was done five days before a likely injury to ‘thin down the blood’. Two respondents fed the leaves and flowers of male papaya plants (Carica papaya) to de-worm pigs.

Husbandry Four respondents gave sour orange juice (Citrus aurantium) to pigs to reduce the fat content of the meat. Three respondents gave coffee grounds (Coffea arabica, Coffea robusta) to scouring pigs.

Reproduction Discussion Three respondents used leaf decoctions of bois canôt (Cecropia peltata) and bamboo (Bambusa vulgaris) for labour pains in pigs or leaves were fed as a postpartum cleanser. The boiled green papaya fruit (Carica papaya) was fed to pigs to induce milk letdown by

All of the plants used for backyard pigs and backyard chickens are commonly known except for eyebright, which has not yet been identified. Eyebright and plantain were reported as ocular medicines in a

Table 1 Medicinal plants used for backyard pigs and backyard chickens in Trinidad and Tobago Common name

Scientific name

Family

Plant part used

Use

No. of users

Aloes

Aloe vera

Liliaceae

Gel

Aloes

Aloe vera

Liliaceae

4 1 4

Bamboo

Bambusa vulgaris Poaceae

Sap from cut leaf Leaf

Internal injuries in backyard chickens ‘Thinning the blood’ Purgative agent for backyard chickens

Papaya Papaya

Carica papaya Carica papaya

Bois canôt Cecropia peltata Worm grass Sour orange Lemon

Chenopodium ambrosioides Citrus aurantium Citrus limonia

Coffee

Coffea arabica C. robusta Immortelle Erythrina pallida E. micropteryx Cotton Gossypium sp. bush Eyebright Not yet identified Planten Plantago major Acrocomia Gru gru aculeataa boeuf a A. ierensisa a

Tentative identification.

Decoction to ease pig labour pains or fed as a postpartum cleanser Caricaceae Green fruit Decoction to induce milk let-down in pigs Caricaceae Leaves, Fed to deworm pigs flowers Cecropiaceae Leaf Decoction to ease labour pains in pigs or fed as a postpartum cleanser Chenopodiaceae Plant tops Anthelmintic for backyard chickens Rutaceae

3 2 2 3 7

Rutaceae

Juice, pulp Juice included in pig diet before slaughter to reduce fat, 4 Toughen and clean cocks’ skin Juice, pulp Used for upper respiratory problems and as a purgative in 6 backyard chickens Grounds Given to scouring pigs in drinking water 3

Fabaceae

Leaf

Malvaceae − Plantaginaceae Arecaceae

Rutaceae

2

Leaves

Crushed leaves added to drinking water to remove dead piglets from uterus Anthelmintic for backyard chickens

Leaves Leaf juice Kernel oil

Ocular injuries in backyard chickens Ocular injuries in backyard chickens Makes cocks’ skin greasy

1 2 No longer used

3


previous publication (Lans, 2001). Eyebright was included in the results for the information of future researchers who may succeed in identifying the plant. The use of Chenopodium as an anthelmintic was so well established that respondents did not consider it ‘new’ information of interest to a researcher and had to be specifically asked whether they used the plant. Dosages Ethnoveterinary dosages could be described as case and context specific, rather than a specific set of guidelines (Eldridge, 1975; Longuefosse and Nossin, 1996). Folk medicine in the Caribbean has had an ‘extra-legal’ status (prescribing is not legal but also not prosecuted) that may account for the reluctance to provide details and specifics on dosages. It may be that drugs are given ‘to effect’, to achieve clinical improvement rather than complete elimination of the causative agent (Eldridge, 1975; Longuefosse and Nossin, 1996). Non-experimental validation A non-experimental validation of the medicinal plants was used to establish their potential efficacy and to check for toxicities. The published phytochemical and pharmacological information was reviewed in order to search for the known physiological effects of either the crude plant or related species, or isolated chemical compounds that the plant is known to contain; and these are presented. This was done to determine the extent to which the folk medicinal data can be understood in terms of bioscientific concepts and methods. An assessment is then made as to whether the plant use is based on empirically verifiable principles. The reported pharmacological literature is then used to give an indication whether there is a plausible biological mechanism by which the plant chemicals and known or possible physiological effects could achieve the results described by the respondents. If sufficient data are available, a level of confidence can be assigned to the plant appraisal. Browner and colleagues (1988) and Heinrich and colleagues (1992) established four levels of validity or confidence: 0 If no information supports the use, this indicates that the plant may be inactive.

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1 A plant (or closely related species of the same genus) that is used in geographically or temporally distinct areas in the treatment of similar illnesses attains the lowest level of validity, if no further phytochemical or pharmacological information validates the popular use. Use in other areas increases the likelihood that the plant is active against the illness. 2 If, in addition to the ethnobotanical data, phytochemical or pharmacological information also validates the use in Trinidad and Tobago, the plant is assigned a higher level of validity. Plants in this category may exert a physiological action on the patient and are more likely to be effective remedies than those at the lowest level of validity. 3 If ethnobotanical, phytochemical and pharmacological data support the folk use of the plants, they are grouped in the highest level of validity and are most likely to be effective remedies (Browner et al, 1988; Heinrich et al., 1992).

Review of known biological effects of the plants and their constituents The ethnoveterinary uses of Aloe vera in Trinidad, included treating internal injuries and purging backyard chickens and ‘thinning their blood’. An infusion of the fresh juice of Aloe barbadensis is used for urinary and bladder conditions and for cleaning the blood in Mexico (Lans and Brown, 1998). Aloe vera is used for supportive therapy and prophylaxis in commercial poultry production in Trinidad and Tobago and is used for internal injuries and as a purgative for ruminants (Lans and Brown, 1998). Fresh Aloe vera leaves are used to obtain two components: (a) a bitter yellow juice (exudate) with high content of 1,8-dihydroxyanthraquinone derivatives (aloe emodin, chrysophanol) and their glycosides (aloins), which are used for their cathartic effects; and (b) a mucilaginous gel from the parenchymatous tissue, which is used for topical treatment of skin burns and wounds (Vázquez et al., 1996). Aloe vera has a significant influence on the proteoglycans and glycosaminoglycans in healing wounds and this healing may be related to mannose 6phosphate and acemannan (Chithra et al., 1998). Cinnamoyl-C-glucosylchromone in Aloe barbadensis

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contributes to its topical anti-inflammatory activity (Hutter et al, 1996). Plant extracts containing anthraquinone have been used globally for centuries for their laxative and cathartic properties (Alves et al., 2004). Anthraquinones have a wide variety of pharmacological activities such as anti-inflammatory, wound healing, analgesic, antipyretic, antimicrobial and antitumour activities. Barbaloin is the major anthraquinone of Aloe vera exudates. The cleavage of the glycoside moiety of barbaloin by intestinal flora leads to the formation of its aglycone derivate, aloe-emodin, which has a stronger laxative effect. It acts through water accumulation in the intestine via active Na+ transport or by water secretion due to a prostaglandindependent mechanism (Alves et al., 2004). Trinidadian farmers used a decoction of bamboo leaves for reproductive conditions in pigs. Cecropia peltata and Bambusa vulgaris are used as ethnoveterinary remedies for retained placenta in other species and the similar ethnoveterinary use for pigs may reflect this. Since factors are related to retained placenta, the crude protein content of the leaves is provided for C. peltata, Bambusa species and Erythrina species. Bambusa species were one component of two multi-plant herbal preparations evaluated for their effects on fertility in rats and buffaloes (Bhaskaran and Kshama, 1999). Bambusa species fresh leaf juice had weak ecbolic action on isolated human and rat uteri. Uterine stimulation was due to its action on cholinergic receptors (Lans, 2001). Bambusa species contains choline, betaine, nuclease, urease, proteolytic enzymes, diastatic and emulsifying enzymes, and a cyanogenic glucoside (Lans, 2001). The crude protein content in bamboo species leaves ranged from 9% to 19% and the crude fibre content from 18% to 34% (Singh, 1999). The methanol extract of leaves of Bambusa arundinacea contained flavonoids, glycosides, traces of alkaloids and phytosterols. The extract contained no proteins, amino acids, tannins, fixed oils, volatile oils or steroids. A dose of 200 mg/kg (i.p.) of the methanol extract had a significant antiinflammatory effect. Doses of 50, 100 and 200 mg/kg of the methanol extract showed ulcer score ‘0’, significant in comparison to control animals (Muniappan and Sundararaj, 2003). The methanol extract of B. arundinacea showed antihypersensitivity activity, immunosuppressive activity, wound healing properties and antibacterial activity experimentally. The LD50 of the methanol extract was 1812.5 mg/kg (i.p.) and


2552.2 mg/kg (p.o.) (Muniappan and Sundararaj, 2003). Middle shavings of stem of B. tuldoides Munro are one ingredient in the Korean herbal formula called Ondamtanggagambang, which is prescribed for psychological relaxation. The formula may reduce blood pressure through enhanced parasympathetic tone and reduced sympathetic tone. It may be useful in the prevention of oxidative stress-induced myocardial damage (Kim et al., 2006). Papaya had two ethnoveterinary uses for pigs in our study: to induce milk let-down and as an anthelmintic. Carica papaya latex extract increased rat uterine contractile activity in pro-oestrus and oestrus stages of the oestrous cycle compared to metoestrus and dioestrus stages (Cherian, 2000). The crude papaya latex contained a uterotonic principle, suggested to be a combination of enzymes, alkaloids and other substances, which can evoke sustained contraction of the uterus by acting mainly on the αadrenergic receptor population of the uterus at different stages (Cherian, 2000). The compounds responsible for the uterotonic activity may also be responsible for the induction of milk let-down by also stimulating contraction of the smooth muscle around the mammary alveoli. The fruit juice of ripe and unripened fruit of C. papaya may contain antihypertensive agent(s) and showed significant antibacterial activity (Emeruwa, 1982). The antibacterial and other properties of the plant may play a limited role in controlling the genital tract infections that may lead to retained placenta (Lans, 2001). Carica papaya leaves contain papain, chymopapain and lysozyme proteolytic enzymes that may have anthelmintic effects (Lans, 2001). Latex collected from young papaya fruits and sap demonstrated anthelmintic activity against Ascaridia galli and Heterakis gallinae infections in chickens; against Heligmosomoides polygyrus infections in mice; in sheep artificially infected with Haemonchus contortus (0.75 g/kg bodyweight); and against natural infection of Ascaris suum in pigs (Eno et al., 2000; Satrija et al., 1994, 1995; Murdiati and Beriajaya Adiwinata, 1997, Singh and Nagaich, 1999; Kumar et al., 1991). The anthelmintic principle of C. papaya is said to be benzyl isothiocyanate and this compound has activity against A. suum (Githiori et al., 2006). In Latin America Cecropia peltata is used for diarrhoea, ‘bad belly’, as an emmenagogue and to ‘wash out the babies’-similar uses to the ethnoveteri-


nary remedy for pigs. Artificially dried leaves of C. peltata contain more than 14% protein (dry matter basis). Free fatty acids including stearic, arachidic, behenic, lignoceric and cerotic acids were isolated from Cecropia species (Duke, 2000; Lans, 2001). The fresh aerial parts of Chenopodium ambrosioides contain an essential oil that has ascaridol as its main component (MacDonald et al., 2004). Ascaridol is a known anthelmintic; however, aqueous extracts of C. ambrosioides did not have any effect against an experimental infection of Ascaridia galli in chickens (Berchieri et al., 1984). Aqueous infusions of C. ambrosioides have nematocidal activity with less than 11% of this activity being due to ascaridole (Berchieri et al., 1984; MacDonald et al., 2004). In this study citrus juice was used to produce lean pigs. It was also used to toughen and clean the skin of cocks and for upper respiratory problems and as a purgative in backyard chickens. Citrus species are used as supportive therapy for many disease conditions and for heat stress in commercial poultry in Trinidad and Tobago (Lans and Brown, 1998). Aqueous decoctions of Citrus species have shown antimycotic, antihaemorrhagic and antibacterial activity (Lagreca and Marotta, 1985; Latshaw, 1991). The vitamin A and C content of Citrus species may also be useful. Vitamins A and C are antioxidants. Vitamin A is important for the health of epithelial, respiratory and ocular tissues. Vitamin C also helps poultry combat stressful conditions (Latshaw, 1991). Four per cent Citrus pectin added to the diet of 40 pigs (divided into two groups of treatment and control) during the finishing period (71–103 kg live weight) produced a highly significant (p