A Comprehensive and Critical Review on Ethnopharmacological Importance of Desert Truffles: Terfezia claveryi, Terfezia boudieri, and Tirmania nivea

Proapoptotic and Antiproliferative Effects of the Desert Truffle Terfezia boudieri on Colon Cancer Cell Lines

Background

Colon cancer is the second leading cause of cancer-related mortality, and ranks third among cancers in terms of prevalence. Despite advances in early detection and treatment with chemotherapy and surgery, colon cancer continues to be associated with high recurrence rates, thereby resulting in a heavy disease burden. Moreover, the effectiveness of currently available treatment modalities is limited by the occurrence of toxic side effects. Hence, there is an urgent need to develop alternative treatments. Extracts from the black desert truffle Terfezia boudieri (T. boudieri) have shown promising anticancer properties. However, the cellular mechanisms underlying this activity remain poorly understood.

Methods

In this study, the colon cancer cell lines HCT-116 and Caco-2 were treated with either water or ethanolic extract of T. boudieri. Cell viability and the half-maximal inhibitory concentration were determined using MTT assays. Then, the activity of the more potent water extract was further verified using crystal violet assays, and its role in inhibiting colony formation and wound healing was investigated. Protein levels of p53, B-cell lymphoma 2 (Bcl-2), Bcl-2-associated X (Bax), cyclin D1 (CCND1), and c-Myc were measured in cells treated with different doses of the water extract.

Results

Treatment with the water extract of T. boudieri reduced the capacity of cells for wound healing and colony formation in a dose-dependent manner. The Bax/Bcl-2 ratio and p53 expression were elevated in both cell lines. In contrast, the levels of cyclin D1 and c-Myc were suppressed.

Conclusion

T. boudieri water extract exerted a cytotoxic effect on colon cancer cells, and blocked colony formation and wound healing potentially through inhibition of proliferation. Mechanistically, these effects are attributed to influence the mitochondrial pathway of apoptosis, proteins involved in cellular proliferation, and the cell cycle.

HPLC and GC-MS based metabolic profiles and in vivo anticonvulsant, sedative, and antinociceptive potentials of truffles Tirmania nivea and Tirmania pinoyi hydromethanolic extracts in mice

GC-MS and HPLC analyses of the hydromethanolic extracts of the truffles Tirmania nivea (TN) and Tirmania pinoyi (TP) revealed the presence of 18 metabolites and 11 polyphenols, respectively. In vivo, TP extract protected against subcutaneous pentylenetetrazole (scPTZ) and maximal electric shock (MES)-induced convulsions faster than TN. TP (100 and 300 mg/kg) showed 100% protection and longer duration than TN in the scPTZ test. Similarly, at 300 mg/kg, TP demonstrated a quicker start (75%) and longer duration of action (100%) than TN in MES test. In scPTZ test, ED₅₀ of TP demonstrated greater anticonvulsant efficacy than TN. In mice given TP and TN treatments, the brain GABA levels were noticeably increased. TP (100 and 300mg/kg) produced a notable sedative effect in open field test, whereas TN (100 or 300 mg/kg) and TP (300 mg/kg) reduced sleep latency by 79, 52, and 45%, respectively. In writhing test, TN (100 or 300mg/kg) significantly enhanced analgesic efficacy by 50 and 87%, respectively. Comparatively, in formalin test, TP and TN at a dosage of 300 mg/kg decreased the length of the licking by 34 and 59%, respectively. For the first time, this study explains the anticonvulsant, sedative, central, and peripheral analgesic activities of truffle extracts.

In Vitro and In Vivo Antidiabetic Activity, Phenolic Content and Microscopical Characterization of Terfezia claveryi

Terfezia claveryi (T. claveryi) is used by traditional healers in the Middle East region to treat several diseases, including diabetes. The present study evaluated the total phenolic and investigated the blood-glucose-lowering potential of different aqueous extracts of this selected truffle using in vitro and in vivo models. The phytochemical profile was examined using UPLC-MS. The macerate and the microwave-assisted extract were the richest in phenolic compounds. All T. claveryi extracts exhibited a remarkable α-glucosidase inhibitory effect in vitro, with an IC50 of 2.43, 3.26, 5.18 and 3.31 mg/mL for the aqueous microwave-assisted extract macerate, infusion and decoction, respectively. On the other hand, in the high-fat diet alloxan-induced diabetic mice model, all tested crude aqueous extracts exhibited a significant antihyperglycemic activity (p < 0.05). Four hours after the administration of the 250 mg/kg dose, the macerate was able to induce a 29.4% blood-glucose-lowering effect compared to a 24.8% reduction induced by the infusion, which was sustained for a further two hours. The hypoglycemic effect (29.3% and 32.4%) was also recorded six hours after the administration of the single dose 500 mg/kg of the macerate and the infusion, respectively. Truffle extracts exhibited antidiabetic activity both in vitro and in vivo, providing a rationale for the traditional use as a natural hypoglycemic.

Biochemical Profile by GC-MS of Fungal Biomass Produced from the Ascospores of Tirmania nivea as a Natural Renewable Resource

The edible fruiting bodies of desert truffles are seasonally collected and consumed in many regions of the world. Although they are very expensive, they are bought and sold as a result of considerable scientific reports confirming their health and nutritional benefits. This study aimed to conduct laboratory production of the fungal biomass of Tirmania nivea as a natural renewable resource of many active biological compounds using an artificial growth medium. The T. nivea collected from Hafar Al-Batin, which is north of Saudi Arabia, and their ascospores were harvested and used to produce fungal biomass in potato dextrose broth. The cultivation was conducted using a shaking incubator at 25 °C for two weeks at 200 rpm. The crud extracts of the fungal biomass and mycelium-free broth were prepared using ethyl acetate, methanol and hexane. Preliminary gas chromatography-mass spectrometry (GC-MS) analysis and their biological activity as antimicrobial agents were investigated. The results showed that the crude extracts have biological activity against mold, yeast and bacteria. The preliminary GC-MS analysis reported that the fungal biomass and extracellular metabolites in the growth medium are industrial renewable resources of several biological compounds that could be used as antifungal, antibacterial, antiviral, anticancer, antioxidant, anti-trypanosomal and anti-inflammatory agents.