Background
Use of natural products as an alternative to conventional treatment for various diseases has been on the rise in the last few decades [
1]. In public concern about dietary and health issues, the increase in the consumption of fungal food have been reported on a global basis [
2]. Besides nutritional value which have industrial applications, many species of
Termitomyces are cited to possess medicinal properties [
2,
3]. In the last few decades, research has been focused on antibacterial, antifungal effects of mushroom. Nosocomial agents such as;
Escherichia coli, Pseudomonas aeruginosa, Enterococcus spp., Streptococcus spp., Candida albicans, and Enterobacter cloacae have long been designated as the most frequent microorganisms causing bacteremia and fungemia [
4]. Thus, various studies are focused to the use of plants or mushrooms as therapeutic agents against these agents. In addition, the effects on the immune system as the most therapeutic effects of medicinal plants in the treatment of infectious diseases have been demonstrated [
5,
6].
Mushrooms have been used extensively in traditional medicine throughout the world. Several species, have been identified as potent immunomodulators or bactericide and they are used to treat infections [
6,
7]. In several studies it was demonstrated that mushrooms of the genus
Termitomyces possess the immunomodulatory or antibacterial activities [
7].
Termitomyces clypeatus R. Heim is among the most common popular edible and medicinal mushrooms in many tropical countries including Brazil, India, Philippine and Cameroon [
8‐
11]. It is recommended by the traditional healers to treat some gastrointestinal infectious diseases. However, no study was done to exhibit its pharmacological properties.
In the present study, Termitomyces clypeatus was tested for its immunomodulatory and antimicrobial activities.
Discussion
Many medicinal mushrooms are used to treat various specific health problems [
13,
16]. As can be seen in Table
2, the extract of
T. clypeatus showed activity on the other test microorganisms (2.5–10.5 mm). The result of this study on the antimicrobial activity of
T. clypeatus showed activity against
S. aureus,
E. coli and S. thyphimurium,
E. aerogenes,
C. albicans and
C. glabrata at different ratios. This may be indicative of the use of
T. clypeatus in treatment of several infections. The significant difference in the size of inhibition between the microbial species could have arisen from the dissimilar biochemical pathways utilized by the pathogen [
17].
Modulation of immune responses to alleviate infectious diseases has been of interest for many years. [
18] One of the major immune response associated with the elimination of bacteria and fungi is the humoral response. Antibodies function as the effectors of the humoral response by binding to antigen and neutralizing it or facilitating its elimination by cross-linking to form clusters that are more readily ingested by phagocytic cells [
19,
20]. The results of the study of the effect of
T. clypeatus on antibody production are depicted in Table
3. The results showed that the extract increased dose-dependently the antibody titer in treated mice groups, but up 1000 mg/kg no significant difference has been observed when compared to untreated control (distilled water). In contrast, the extract has significantly reversed the inhibitory effect of dexamethasone. Despite the fact that the increase in production of antibody is not significant, the results indicate that the extract may stimulate the secretion of antibodies. This can be a result of the stimulatory activity of
T. clypeatus on the secretion of antibodies by activated plasma cells or on the secretion of cytokines such as IL-4 from activated T lymphocyte cells [
21]. Thus, this effect may be justify the reversion of the inhibitory effect of dexamethasone by the extract. Dexamethasone + levamisole group showed significant increase in HA titer as compared to dexamethasone + distilled water control group. This is evident since levamisole is known to restore corticosteroid induced depletion of immune response. Therefore, the extract may be had similar activity. An increase in production of antibodies may be an evidence of the importance of this mushroom demonstrated by the low mortality rate seen in
T. clypeatus treated mice infected by
P. multocida compared to control untreated.
The skin thickness increase was lower in the dexamethasone group when compared to the control. When compared to control,
T. clypeaus and levamisole showed significant increase in skin thickness. Also, when compared to dexamethasone, Dexamethasone +
T. clypeatus, Dexamethasone + levamisole showed significant increase in skin thickness. It has been demonstrated that DTH response results from the action of sensitized T lymphocytes, when challenged by antigen and were secrete a variety of molecules including proinflammatory lymphokines attracting more scavenger cells to the site of reaction [
22]. Increased DTH response in treated animal showed that
T. clypeatus might has a stimulatory effect on the lymphocytes and accessory cell types required for the expression of this reaction. A stimulatory activity on lymphocytes can boost phagocytic activity and increase concentration of lytic enzymes for more effective killing, which ultimately results in increase footpad thickness in immunized animals [
23]. This suggests that
T. clypeatus could enhance T cells proliferation and expression of the adhesion molecules, thus increasing migration of T cells to the site of inflammation.
Body weights of mice in treated groups decreased from the control or the dexamethasone groups indicating that the consumption of
T. clypeatus has changed body weight of animals during the period of the study. Mushrooms and mushroom-derived polysaccharides, have been shown to have therapeutic properties against metabolic syndrome, which is characterized by obesity, hyperglycemia associated with diabetes, hypercholesterolemia, and hypertension [
24‐
26]. This was attributed to their anti-hypercholesteremic effects which result in body weight. Hence the decreased in body weight by the result may be a result of the effect of
T. clypeatus on lipid mass. As low lipid mass could not be affect significantly the production of antibodies or cell proliferation, this could be justify the improvement of immune response by the extract while it lowers the body weight.
T. clypeatus is an edible mushroom, largely consume without adverse effects. Hence, the decreased in the body weight observed could not be compromised its use for its immunomodulatory. Otherwise,
T. clypeatus was administered through oral route in two form as additive aliment (powder) and dissolved in water (extract). As the powder was used in crude form this could be lowered the animal’s appetite which can also result in loss of body weight.