Knowledge and use of wild edible plants and mushrooms in Bamenda Highlands
Cameroon is a culturally diverse country consisting of over 250 ethnic groups, and the cuisine significantly varies by ethnic group and region. Wild foods are essential components for these dishes and the regional cuisine. In the Bamenda Highlands of Cameroon, the Tikares appears to be the most populous ethnic group, and they were the first to settle on the Bamenda region . According to anthropologists, they originated from northern Cameroon and migrated southwards and westwards in the eighteenth and nineteenth centuries to their current locations in the Western Grassfields (Bamenda Highlands) and Eastern Grassfields (Fumban) and the Tikar Plain of Bankim . Despite the scarcity of ethnobotanical literature on wild foods, indigenous communities in this area have gathered wild edible plants and mushrooms for centuries as a strategy to complement their crop-livestock subsistence systems. Each community group has made particular choices among the wild food resources available, and this utilitarian relationship between indigenous communities and the WEPM can be contextualized in space and time. As it was described in temperate ecosystems, the dynamics of this relationship can vary depending on species availability, site accessibility, cultural acceptability, traditional ecological knowledge, migration, changes in lifestyle, and other socio-ecological processes . These factors, according to , can determine the acceptability or a possible replacement of wild foods with modern foods.
In this study, 47 species were recorded. Some, including Ricinodendron heudelotii, Piper guineensis, Cola sp., Tetrapleura tetraptera, Xylopia aethiopica, and Canarium schweinfurthii, have been reported in previous surveys on non-timber forest products in Tikar Plain . Others like bush mango (Irvingia gabonensis), njansang (Ricinodendron heudelotii), eru (Gnetum africanum), and kola nuts (Cola spp.) are also among the key non-timber forest products of Central Africa .
The number of species recorded during this survey does not certainly captures all the diversity of wild edible plants and mushrooms growing in this study area, as their availability rely on seasons. There is generally a relatively high importance of wild edible plants in the rainy season. The period of the survey coincided with the beginning of the rainy season when some species, although not yet providing edible parts, is re-sprouting, flowering, and fruiting. A cross-seasonal investigation will be required to capture the diversity of wild edible plants and mushrooms consumed in the study area.
Also, as argued by several authors, age, gender, and other sociocultural variables are likely to influence access to wild plant resources and the traditional ecological knowledge of wild foods .
Nutritional potentials of wild edible plants and mushroom recorded
Several studies emphasize on the high nutritional importance of wild edible plants [39,40,41,42]. This is true for the species in different groups of WEPM recorded. Their seasonal relative importance greatly impacts the food and nutritional insecurity copying ability of households. Previous studies have confirmed that in times of food scarcity, they make human diets more diverse and add flavor, vitamins, and minerals .
The highly exploited wild vegetable Gnetum spp., locally called “eru” is very rich in proteins and minerals (Na, K, Ca, Mg, Fe) and contains all essential amino acids .
Waterleaf (Talinum triangulare) is reported to be very rich in carbohydrates, protein, steroid, oil, b-Carotene, crude fibers, and minerals like Ca, Mg, Na, and K .
Elemental analysis in mg/100 g (DW) of leaves of Amaranthus hybridus was done by previous studies . These authors indicated that the leaves contained sodium (7.43), potassium (54.20), calcium (44.15), magnesium (231.22), iron (13.58), zinc (3.80), and phosphorus (34.91). The vitamin composition of the leaves in mg/100 g (DW) was as follows: carotene (3.29), thiamine (2.75), riboflavin (4.24), niacin (1.54), pyridoxine (2.33), ascorbic acids (25.40), and -tocopherol (0.50). These authors also reported 17 amino acids (isoleucine, leucine, lysine, methionine, cysteine, phenylalmine, tyrosine, threonine, valine, alanine, arginine, aspartic acid, glutamic acid, glycine, histidine, proline, and serine) detected in leaves of this species. Alkaloid, flavonoid, saponin, tannins, phenols, hydrocyanic acid, and phytic acid composition were 3.54, 0.83, 1.68, 0.49, 0.35, 16.99, and 1.32, respectively. These evidences are indication that the leaves of Amaranthus hybridus are important source of nutrients, minerals, vitamins, amino acids and phytochemicals, and low levels of toxicants.
For Corchorus olitorius, the proximate and mineral composition of leaves were investigated in Nigeria  and showed that the leaves contained 18.38 ± 0.32% ash, 12.54 ± 0.10% crude protein, 11.99 ± 0.50% crude lipid, and 19.56 ± 0.18% available carbohydrate. Their energy value reported was 200.78 ± 3.54 kcal/100 g. On the other hand, their mineral content comprises potassium (2814.15 ± 8.08 mg/100 g) and magnesium (76.69 ± 0.13 mg/100 g) as dominant elements, Na (54.56 ± 0.42 mg/100 g), Ca (30.55 ± 0.05 mg/100 g), P (6.68 ± 0.02 mg/100 g), Cu (2.52 ± 0.02 mg/100 g), Fe (19.53 ± 0.09 mg/100 g), Mn (5.95 ± 0.04 mg/100 g), and Zn (4.71 + 0.01 mg/100 g). These findings support the use of Corchorus olitorius leaves are rich sources of potassium, iron, copper, manganese, and zinc as well as high energy values essential in human nutrition. Antinociceptive/anti-inflammatory, anti-tumor, antipyretic, carminative, demulcent, laxative, stimulant, and stomachic properties were also reported for this species .
Strong free radical scavenging activity was reported for Vernonia calvoana, and the authors of this study concluded that V. calvoana could serve as source of strong dietary antioxidants . Its amino acid composition compare favorably with that of WHO protein standard , and Vernonia calvoana is also rich source of carotenoids (between 30 and 41.5 mg/100 g DW), vitamin C (between 137.5 and 197.5 mg/100 g DW), and dietary fiber (24.9–30.1 g/100 g DW).
Afrostyrax lepidophyllus was investigated for its biological activity and phytochemical composition . Using 3 different extracts, these authors reported tannin content of the order of 2.35 ± 0.3, 10.68 ± 0.1, 7, and 78 ± 0.2 mg eq Cat/g DM. That of anthocyanins were 0.79 ± 0.04, 0.65 ± 0.02, 1.65 ± 0.07, and 0.18 ± 0.03 mg eq C3GE/g MS. These findings support the antioxidant, anti-inflammatory, and anti-xanthine oxidase activity of Afrostyrax lepidophyllus seeds used in the human diet.
Fruits of Mondia whitei contain antioxidant vitamins C and E which had values of 14.50 mg/100 g and 2.45 μg/g, respectively . Potassium and sodium are the most abundant mineral elements. The roots of this species are attracting the interests of cosmeceutical, nutraceutical, and pharmaceutical industries. They are traditionally used for the treatment of anorexia, stress, bilharzia, and sexual dysfunction as well as for general aches and pains. The efficacy of most of these claims have been analyzed several researchers who investigated in the biological activities Mondia whitei roots and reported antimicrobial, anti-inflammatory, and anthelmintic as well as aphrodisiac efficacy .
Piper guineensis is a rich source of calcium (179.52 ± 0.11 mg/100 g), potassium (98.52 ± 0.1011 mg/100 g), and phosphore (217.70 ± 0.41 mg/100 g), and vitamin B2 and C .
Chemical profiling of Xylopia aethiopica revealed the presence of different phytochemicals of various physiological and biological actions. The fruit was reported to contain 38.72 ± 0.61% fiber, 26.08 ± 1.41% carbohydrates, 18.47 ± 0.05% protein, 6.73 ± 0.01% lipid, 6.02 ± 0.84% moisture, and 4.00 ± 0.02% ash, and mineral analysis showed the abundance of some mineral elements in Xylopia aethiopica fruit like calcium, potassium, magnesium, sodium, irons, phosphorus, zinc, manganese, chromium, and copper . It was also reported the presence of alkaloids, cardiac glycosides, saponins, tannins, flavonoids, polyphenols, and reducing sugars, vitamins A, C, and β-carotene, all bioactive substances that may be beneficial to health .
Nutritional potential of Canarium schweinfurthii was investigated in Plateau State in Nigeria . They indicated crude fat of the fruit as 64.04%, protein 6.39%, fibers 16.37%, and carbohydrates 3.85%, respectively. Mineral analysis revealed that phosphorus and sodium levels were 1.74 and 1.369 mg/100 g, respectively. These authors suggested that Canarium schweinfurthii is nutritive despite the presence of some low levels anti-nutritive components like oxalate. The final products will contain even less.
The presence of various phytochemical constituents like flavonoids, tannins, phenol, glycosides, fatty acids, and alkaloids was reported in the fruit of Passiflora edulis , as well as anti-inflammatory, anticonvulsant, antimicrobial, anticancer, antidiabetic, antihypertensive, anti-sedative, and antioxidant properties.
The leaves of Physalis angulata were investigated for their potentials in alleviating micronutrient deficiency . The study found that Physalis angulata fruits have crude protein content of 10.97%, sodium 689.48 mg/100 g, and manganese 21.60 mg/100 g. Amino acid analysis indicated the presence of isoleucine, valine, phenylalanine, tyrosine, and leucine. The reported concentration of phytate/Zn supports its potential into food-based strategy to alleviate zinc malnutrition.
Roots and tubers
The antiprostate cancer and antiangiogenic activity of the roots of Vernonia guineensis were demonstrated, supporting the use of the tubers of this plant for the treatment of prostate cancer .
Records from the database of Plant Resource of Tropical Africa (PROTA) indicate that the fruit pulp of Raphia farinifera contains about 24% oil. The major fatty acids in seed oil are palmitic acid, oleic acid, and linoleic acid. The main sterol is β-sitosterol. The fruit pulp has shown antibacterial activity against Staphylococcus aureus but not against the gram-negative bacteria Escherichia coli, Pseudomonas aeruginosa, and Salmonella typhi; it also had no activity against the fungi Candida albicans and Aspergillus niger.
It is thus clear from various screening of the recorded plants that almost all of them are important from nutraceutical points. Many of the recorded plants are of rich nutritional value as sources of micro and macro elements, roughage, protein, and amino acids without anti-nutritional factors . Local communities in the Bamenda Highlands thus derive important nutrients from these plants. However, some are lacking scientific nutritional knowledge, and many of their values remain either uninvestigated or undocumented because their products are used locally without being reflected in national or international markets. Therefore, systematic documentation of indigenous knowledge regarding the identity and use of wild edible plants is an urgent concern because both biological resources and indigenous knowledge are diminishing with high destruction and a growing disinterest among the younger generation.