Abstract: Kakamega Forest is a rich natural setting endowed with abundant flora and fauna used by the local communities who once lived within the forest and those who now border it. There has been scarcity of information on plants used in basic traditional healthcare by the adjacent communities, Luhya, yet alternative medicine continues to fill in the gap left over by modern medicine. This study sought to survey and document plants used from the forest as medicine or in traditional healthcare and collect, identify and preserve specimens of such plants in the herbarium. Field observation and 240 open-ended interviews conducted during this research have indicated that the people highly value plant medicines for their primary healthcare needs and that the plants are used to cover a wide range of ailments and conditions affecting both man and his domestic animals. The diseases range from topical to internal and psychosomatic ailments, to simple as well as stubborn conditions. Such diseases include whitlow, measles, chickenpox and cancer amongst others. A total of one hundred and twenty herbal practitioners, over 18 years of age, were interviewed between March and September 2002 in this ethno-medicinal study. There have since been bi-annual follow up visits for more information. A total of 168 plant species spanning 74 plant families are reported herein. Moraceae topped the list with 10 species followed by the Euphorbiacea with 9. The most frequently used were Zanthoxylum gillettii, Trichilia emetica, Olea capensis, Entada abyssinica and Croton macrostachyus. The biological diversity, as a phytomedical resource has been indexed thus, contributing to the database of the Kakamega Forest plants. It is hoped that the report will be of use to policy makers. There are several plants with uses hitherto not reported, for instance Craterispermum schweinfurthii an aphrodisiac, Allophylus abyssinica for the hunch back, Ensete edule for measles and Sapium ellipticum for burns. This research has the potential for production and industrialization of the medicinal plants. Medicinal value of plants is hereby fronted as a reason for conserving and preserving biodiversity in Kakamega Forest.

INTRODUCTION

Kakamega Forest, Kenya, forms part of the world’s equatorial forest belt. The equatorial forests in Africa are the extension of the Amazonian forest system in South America (Kokwaro, 1988). As such, Kakamega Forest is a living remnant from the long Pleistocene period when great climatic changes occurred throughout the world. As human population increased, the forests further shrunk getting replaced by savannas or bush leaving behind pockets of forests in Zaire, Uganda and Kenya (KIFCON, 1994). Today, Kakamega Forest covers an area of only 327 km², but remains an important habitat for various species of animals and plants most of which are indigenous making the forest unique (Onyango et al., 2004; RoK, 2002). Timber exploitation continued into 1980s when it was finally realized that the forest was more valuable as a scientific resource than as a source of timber alone (KIFCON, 1994; RoK, 2002). This has fuelled the need to conserve the forest.

In the early 20th century, various Luhya clans established themselves around Kakamega Forest (Were and Wilson, 1968). The Luhya people are the focus of study. This community is rural and practitioners of herbal medicine remain active. Many people still supplement herbal remedies with modern medicine partly due to dearth of services or inadequacy of services rendered at most of the local health institutions and partly due to cultural practices, which still are deeply rooted (Were and Wilson, 1968). The population density of persons km^-2 861-Shinyallu, 1,485-Municipality, 645-Ikolomani and Kabras-352 and intensive land use around this forest is itself a danger to the very existence of the biological diversity of the area (RoK, 2002).

There still is a strong dependence of the Luhya on the use of plants especially for medicine to date. With forest destruction, the Luhya endanger their traditions and livelihood. This ethno medicinal study examines the traditional primary healthcare of the Luhya people around Kakamega forest since it has been little studied. Particular attention has been given to the custodians of Indigenous Knowledge (IK), specifically the healers, practitioners and other knowledgeable members of the society. The findings will expand the data and information available and will be of use to policy makers and health actors, while the custodians of knowledge are still alive and active.

The growth of herbal medicine is on the rise worldwide by the trend of back to nature creating a new niche for plant-based healthcare (Cox, 1994). The WHO and other major bodies have stressed the need to employ traditional healthcare where appropriate in healthcare programs to achieve the health for all goals. This is also, part of the Millennium Development Goals and Vision 2030 for Kenya. Between 35,000-50,000 plants species are used medically yet only about 100 are used to obtain clinically important drugs or drug molecules. There is thus, scope to add to the list of plants used and those that can clinically be used.

MATERIALS AND METHODS

Study focus: Kakamega forest: The Kakamega Forest stretches from 0°10''-0°21''N and longitude 34°47'-'34°58'' E. It is located in Kakamega and Vihiga Districts in Western Province of Kenya and lies within the Lake Basin North of the Equator. The reserve comprises of 5 blocks namely Malava (719 ha), Bunyala (825 ha), Kaimosi (200 ha), Maragoli (720 ha) and the main forest block Kakamega comprising of Isecheno (14.500 ha), Kisere (471 ha) and Buyangu (3,997ha) (Fig. 1).

Data collection: The study focused on the Luhya people. Emphasis was laid on ethno medicine, specifically, the phyto-medicines. The study involved interviews, photo taking and ocular observation. The observations were open, but non participatory so as to get more objective results. The interviews were oral and this required raport. Individuals were preferred to groups because of the nature of information required. The unstructured or semi structured questions allowed the interviewees to give as much information as they could in a conversational atmosphere in a more or less confidential manner.

Fig. 1:	Annex, OGUTU, 1997, 32

Care was taken to avoid lies by confirming surprising answers and by not asking leading questions or those with implied responses. Questionnaire forms were often only filled in later and not during interview sessions. In total, 120 persons were interviewed over the 6-months period between March and September 2002. The local and scientific names were sought.

Specimen collection and processing: The plant specimens were collected, processed and dried in the university drier at 40°C. The ones that could not be identified immediately in the field were taken to the Nairobi University Herbarium (NAI) and the East Africa Herbarium (EA) (also referred to as the National Museums of Kenya Herbarium), for proper identification. Standard taxonomic procedures were diligently followed (Agnew and Agnew, 1994; Beentje, 1994; Judd et al., 2008; Lawrence, 1951; Maundu and Tengnas, 2005; Stace, 1989) to ensure accuracy of scientific names to the corresponding local names. Simon Mathenge of University of Nairobi Herbarium and Kirika of the East Africa Herbarium confirmed the names. Taxonomic recognition of name changes has been given through authorities and synonyms where appropriate. The pressed plant materials were mounted, poisoned and stored as voucher specimens in the University Herbarium, Maseno with duplicates to be deposited at the NAI and EA.

Questionnaires were used but the study situation remained tricky due to the forest management policy (Kenya Wildlife Service side and Kenya Forest Department renamed Kenya Forest Service). Purported remedies were regarded as valid if >3 independent persons gave the same account. But, since knowledge in traditional medical practice is highly secretive, all accounts were recorded for they could represent restricted knowledge that’s very effective in disease management. The rest of the data was subjected to descriptive statistical analysis using Excel.

RESULTS

Plants mentioned by various participants have been listed alphabetically for convenience. Unless otherwise stated, the disease or conditions and associated medicaments are those applicable to man. This summary is a species list that gives more information on tree species cited regarding range (number) of disease the plants can treat, parts used and other local names. The local names are in Luhya, a name that has been preferred to cater for all the dialects available since the adjacent communities are a mix across the various subgroups (Table 1).

Table 1:	Plant list, local names are in Luhya language
bk: bark; fl: flower; fr: fruit; lv: leaves; rt: root; st: stem; tb: tuber; tw: twigs; wp: whole plant; sa: sap; se: seed; rh: rhizome; gu: gum;

DISCUSSION

The survey revealed that information about plants is fairly widespread considering that of the 120 persons interviewed; 110 (91%) gave positive response. Only 10 (9%) totally refused. The 40 confirmed that they knew a lot about plants used in medicine but were reluctant to divulge their knowledge. Of the 110 who gave information, 14 (12.7%) gave uses of plants, but not plant names meaning that knowledge was there; 10 others (9%) gave only two remedies each though they were very knowledgeable; 4 others (3.6%) only listed names of plants used, but not how or for what; the rest (74.67%), majority, gave information freely. If the widespread knowledge was an indicator of potential use, then one could state that plant resources were heavily used in medicine. Out of the 110, who were positive, only 17 (16.36%) were not sure of names of some plants used. Thus, the people had a good folk knowledge of plants.

The local Luhya names provided the key to local biodiversity communication about. The problem is that local names may be general and imprecise. For instance, shikuma refers to two unrelated plants, Clerodendrum and Hoslundia (Verbenaceae and Lamiaceae, respectively). Scientific names provide a precise tool to understand and retrieve information on plants. Documented in this report are 168 plant species of medicinal value. Of these 21 were herbs, 4 were twiners or lianas, 14 were climbers, 45 were shrubs, 82 were trees and 1 creeper. About 75% of these were shrub/tree species. They were spread across major plant families Moraceae and Euphorbiaceae afforded 10 species each followed by Lamiaceae with 9 records. The species range included poisonous plants such as Funtumia africana and Tabernamontana ventricosa. Most records were indigenous taxa though some introduced species such as Cupressus lusitanica, Grevillea robusta, Eucalyptus globulis, Sesbania sesban, Acrocarpus fraxinifolius, Pinus patula Punica granata (Pomegranate) and Melia azedarach ended up in the local pharmacopoeia indicating that culture is dynamic. This study reports on tree species of medicinal value. Other categories will appear in subsequent publications.

Many plant harvesters were only interested in short term gains going by the many dried up and or over debarked trees. Many Trichilia emetica trees had dried up due to poor harvesting. Different plant parts (roots, bark, gum, sap, seeds, fruit, flowers, twigs) were valued for treating varied or similar diseases. This explains why certain specific taxa were targeted for their bark, roots or rhizomes. Root destruction impacts negatively on plants such as Markhamia lutea hence, the forest. Eucalytptus globulis and Melia azedarach amongst others had useful leaves. Under controlled harvest species survival may be guaranteed, but if this fails, sustainability becomes questionable and the future of the forest as well.

Diseases managed, ranged from the common upper respiratory tract infections to reproductive health. That there was such specialized and discrete categories such as barrenness, schizophrenia and stroke inter alia, indicated that the traditional herbal practice was fairly specific and could supplement and complement modern medicine where, appropriate. The herbal remedy for measles, referred to as neem or mwarubaine turned out to be Melia azedarach and not the expected Azadirachta indica. Neither plant is mentioned in Kokwaro (1988). The Azadirachta indica in Maundu and Tengnas (2005) is in fact Melia azedarach, a case of confusion resulting from plants looking alike in vegetative phase. With proper screening, plants and plant products can be isolated and be used for drug development or homeopathic medicine or even industrialization (Gurib-Fakim, 2006; Ludeki et al., 2006).

The high incidence of diseases related to poor hygiene such as dysentery and diarrhea has been attributed to the poor economy hence, poverty, while changing lifestyles and habits have accelerated problems related to the circulatory, respiratory systems and STDs as well as in reproductive health like barrenness and impotence. Though, use by women is now on the increase, mostly men use Craterispermum schweinfurthii as an aphrodisiac. Although, there were antidotes for such stimulants, the knowledge remained a guarded secret hence, lacks in this report. Traditional knowledge pertaining to such stimulants was widespread, a pointer to their efficacy.

The fact that there were medications for problematic diseases like mental illness, stroke, syphilis, cancer and urinary tract infections, medications for congenital anomalies like the hunch back, resistant fungal skin infections and medications for pre-and post-natal care for mother and child showed that primary healthcare was strong. Considering that many dermatological conditions are resistant and difficult to treat yet are purportedly managed traditionally suggests that a lot of scientific gains can be made from this report. There was a precautionary note whenever toxic plants appeared in the local pharmacopoeia; Funtumia africana, Antiaris toxicaria and Ficus sycomorus are examples. Considering that many Western drugs originated from toxic plants through phytochemical studies, for instance Digitoxin and Digoxin from Digitalis, it is probable that such plants could in future prove to be sources of new drugs (Arwa et al., 2008; Mcgaw and Eloff, 2005; Onyango et al., 2004).

Zanthoxylum gilletii seeds are also used in spicing tea, favored for its medicinal value against flu and common chest ailments. Toddalia asiatica and Zanthoxylum gillettii twigs are also used as toothbrushes. Other than stimulating, the gums and removing food particles, they have antimicrobial properties (Sofowora, 1982). The Zanthoxylum has been shown to contain antimicrobial derivatives and alkaloids against common oral infections (El-Said et al., 1971). Though herbal, remedies appeared specialized, the same preparation could be used against other specified diseases making them appear general and broad range in action.

In this report, the most heavily utilized remedies were arboreal species (75%). The most targeted taxa were Trichilia emetica, Harungana madagascariensis, Entada abyssinica, Zanthoxylum gillettii, Fagaropsis angolensis, Olea capensis, Croton macrostachyus and C. megalocarpus and Prunus africana. There is a strong scientific basis for plant use in medicine. Combretum and Zanthoxylum have been shown to contain potent anti-microbial activity (Masoko et al., 2007; Sofowora, 1982). This possibly explains why Combretum is used to clear skin warts, while Zanthoxylum features across divergent medications ranging from chest conditions, sore throat, skin rashes and scabies, gut problems, general illnesses and gonorrhea amongst others. This is in line with findings that Combretum contains combrestatins that inhibited the growth of several human leukaemia and solid tumour derived cell lines in vitro and in vivo (Hartwell, 1982; Powis, 1994) and have the capacity to inhibit tubulin polymerization as well as the ability to suppress angiogenesis (Dark et al., 1997; Dorr et al., 1996; El-Zayat et al., 1993; Pettit et al., 1998). Combretum also contains antioxidants (Masoko and Eloff, 2007). Cold infusions of O. gratissimum have been shown to contain thymol, which is both anthelminthic and antimicrobial hence, its antidiarrheal effects. Its aqueous decoctions have no antibacterial effect but have been shown to calm down gut muscles in vitro hence, their use in controlling gut related problems hence, its traditional use.

Tannins are known to occur in the bark of trees and shrubs (Kokwaro, 1993) hence, their use in herbal medicine. The low solubility of tannins and their ability to coagulate proteins has been exploited medically in cases of diarrhoea and dysentery and even the urinogenital system (Eldin and Dunford, 1999). The Acacia sp. are rich in gallotannins and catechins, which explains why they are used in against diarrhoea (Sofowora, 1982). The bark of Albizzia and Acacia are rich in not only tannins but also gum. The tannins are capable of precipitating proteins thereby aiding in wound healing while, the gums act as emulsifying agents in the gut (Kokwaro, 1993; Sofowora, 1982). Zanthoxylum has been known to contain analgesic, antibiotic and counter-irritant properties hence, its use in treating flu, toothache, rheumatism, cancer, sickle cell and snakebites amongst others (El-Said et al., 1971; Hesse, 2002). Though, the bark and root are used most often, research has proved that antisickling compounds are richest in the leaves.

There were hardly any cases of schisostomiasis encountered, attributed to the widespread Croton macrostachyus whose seeds have molluscidal properties (El-Kheir and Salih, 1979). The informants felt there were more cancer cases. This could be due to changing habits and lifestyles, for instance sweet potatoes, Ipomoea batatas was a common food as well as wild fruits like Physalis peruviana. This is not the case any more yet Ipomoea has been found to contain lung-cancer-specific pneumotoxic furan derivative, an antineoplastic agent, while Physalis contains physalin an antileukemia lactone (Chiang et al., 1992a, b; 1992; Cragg and Suffness, 1988; Rowinsky et al., 1993).

In general, plant drugs were mainly administered in liquid form as decoctions, infusions and gargles among others. Solids like charcoal (carbon) or semi carbon dust, powders or ash were occasionally applied on wounds, burns and the tongue among others. Only in two cases was latex, a semisolid material administered. Topical applications included steam inhalation as in steam bath or regular bath, poultices or ointments or skin incisions. This would enable the drug to reach body tissues fast through body orifices and the lungs. With 75% of plants used belonging to category of trees and shrubs meant that too much extraction would be deleterious to the forest since there is a 75% chance that a remedy collected from the forest is likely to be from a tree. Climbers and monocots were seldom used. The parts used range between roots, leaves and twigs from trees, shrubs and climbers. The use of inflorescence (as in Ensete edule) or fruits (as in Kigelia africana) was rare. Tree species are too big to be used as whole plants, hence, the parts.

Certain aspects of herbal knowledge were localized and restricted within the community. As such remedies for snakebites, feminine conditions, bone fractures and anemia were hardly cited and guarded yet those for diarrhea, malaria, STD and stomachache were readily available (Owuor et al., 2005). There are new findings. Burn treatment with Sapium ellipticum and Spathodea campanulata with positive results is new. Allophylus abyssinica is used to straighten up the extra curvature of the spinal column in those with the hunchback, best used during the early stages of onset and C. schweinfurthii an aphrodisiac are new findings. Such plants could be used in poverty alleviation through sales of parts or seedlings. The medicinal value of plants is therefore, fronted as a reason for conserving Kakamega forest.

CONCLUSION

This research has provided a detailed and comprehensive documentation of some of the commonly used medicinal plants in Kakamega forest, hence the need to conserve the forest. Report covers new uses and new records. It confirms how plants can be used to improve the value of the environment and reduce human suffering.

ACKNOWLEDGEMENTS

BIOTA E12 of the Ministry of Education and Research, Germany, for financial support. My assistants Patrick Omulubi (Maseno University) and Henry Makhola (KABICOTOA), Kakamega.KEEP and the members of the community living adjacent to Kakamega forest, on whom the information is based.