The Therapeutic Potential of Phytomedicines from Brazilian Cerrado Herbs against Neurodegenerative Diseases

Introduction

Plant metabolism is acknowledged to be highly variable, what nonetheless confers complexity and wide range of therapeutic applicability. In this context, the myriad of metabolic outputs promoted by vegetal biochemical pathways allows the synthesis of diverse compounds which might be useful in healthcare. Amongst the most common metabolic outputs, phenylpropanoid and polyketide pathways are often associated to molecules of medicinal interest, whose biological activities might undergo synergism when herbal preparations are used [1, 2]. Henceforth, the pharmacognostic assessment of plant material is highly regarded to shed light on their biological properties [3, 4].

Ethnopharmacological reports evidence that medicinal plants are the first intervention of many folk medicine practices, what shows the importance of investigating these natural remedies in order to ensure therapeutic success and patient safety. Concerning the treatment of dementia, herbal medicines are widely used to alleviate symptoms and halt disease progression, being these applications manly supported by the antioxidant potential of vegetal raw mater [5, 6]. Notwithstanding, folk medicine practices have guided many phytopharmacological interventions towards the handling of neurodegenerative diseases, and these approaches are considered promising remedies to improve patient prognostic [7, 8].

Regarding the use of medicinal plants against dementia, Brazilian Cerrado-flora presents itself as a valuable source of biologically active herbal mater. Given that Cerrado biome is known to harbor a plethora of vegetal varieties used in regional folk medicine, it is safe to say that the use of these plants by overall western medicine is still being unravelled [9,10]. Although previous reports contributed to shed more light on the applicability of Cerrado plants against neurodegenerative diseases, more investigations are needed in order to explore the pharmacological potential of this biome [11, 12, 13]

In view of the importance that Cerrado-flora presents as promising anti-dementia medicines, this short commentary is intended to evidence the latest advances reported in literature about the use of native herbs of this biome against neurodegenerative diseases.

Cerrado-flora biochemical complexity against dementia

Plant secondary metabolism is regarded as one of the main sources of medicines, which might be used either through standardized pharmaceutical formulations or folk medicine preparations. Literature evidences several benefits from using plant-derived products in healthcare, due to the synergic effect promoted by phytomedicines [1, 2, 3, 4]. Since plant metabolism allows the biosynthesis of widely diverse chemicals, this pool of compounds may interact with bodily receptors via potentiation, further enhancing the biological activity and henceforth, the appeal of natural products in pharmacology [14, 15].

Considering that highly biodiverse biomes are stated to harbor vegetal varieties whose chemical arsenal might find use in healthcare, the investigation of native species is well regarded in the scope of drug-discovery. Nonetheless, biomes such as Brazilian Cerrado are targeted by local and foreign research groups in the exploration of therapeutically useful herbs. Cerrado is located in the central-western region of Brazil and consists of a highly variable landscape under intertropical climate. This biome shares many climatic and edaphological similarities with the African savannah and plays a distinct role in both Brazilian culture and economy [12, 16]. Moreover, Cerrado relevance is also showcased in healthcare, since many herbs are used by local population in folk medicine remedies [16, 17].

Amongst the diseases whose Cerrado plants might be used against are dementia. These sicknesses are neurodegenerative conditions which affect mostly the elder population and are marked by cognitive and motor impairment. Although dementia refers to a broad category of brain diseases, most share similar traits, such as the overall symptoms as well as pathogenesis, which might include oxidative damage, aberrant protein expression and cholinergic signaling impairment [17, 18]. Most dementias are not curable according to contemporary medicine, and treatment consists of support therapy to alleviate symptoms. Although pharmacotherapy with cholinesterase inhibitors did enhance the quality of life of patients in some studies, the overall pharmacologic response is still highly variable [19, 20].

Regarding Cerrado-flora potential against dementia, many reports showcased that several plants presented remarkable neuroprotective properties, what suggests that these plants might be useful to improve patient prognostic [10, 11, 12, 13].

Antioxidant and anticholinesterase properties of Cerrado flora

Concerning the chemical richness showcased by Cerrado plants, literature reports evidenced that these herbs present myriads of phenylpropanoid and polyketide metabolites whose therapeutic potential is yet to be used in medicine. Although almost all species of vegetal kingdom present ubiquitary compounds such as shikimic, gallic or ellagic acid, Cerrado plants showcase remarkable concentrations of either these compounds or their derivatives e.g. polyphenols [21, 22]. Moreover, polyketide derivatives such as coumarines, furanocoumarines and anthraquinones are also readily available in underground parts of the plants i.e. roots [23, 24].

Nonetheless, all these compounds do present some degree of biological activity, however, when neurodegenerative diseases are concerned, their radical scavenging potential is highlighted. As previous reports further evidenced, plant secondary metabolites of phenolic nature do exhibit thermodynamic proneness to not only stabilize reactive oxygen species [25, 26, 27], but also restitute endogen antioxidants [10, 11, 12, 13]. This characteristic has deep implications in the management of neurodegenerative diseases, since their progression is often associated to oxidative stress [24, 28, [29, 30, 31]. Notwithstanding, some of these metabolites also showcase proneness to inhibit acetylcholinesterase and butyryl cholinesterase, what further support their potential in the treatment of dementia [10, 11, 32].

Although the bulk of antioxidant and anticholinergic activity is attributed to the presence of phenolic derivatives, the biological activity of Cerrado plants is not only associated to thermodynamic feasibility of reactive oxygen species reduction and punctual enzyme interactions, but also to the chemical variety of phytoconstituents, which may allow them to bind to several distinct receptors in the human organism.

Literature reports that extracts from Cerrado plants promote vasorelaxation, as well as chemoinformatic studies indicate that secondary metabolites might interact with several receptors, henceforth leading to anti-inflammatory, anti-pyretic and anticancer activities [33, 34, 35, 36]. Considering the complexity of the molecular basis of many neurodegenerative diseases, the potential of Cerrado plants to treat these as well as other disorders might be somewhat linked to such variety regarding biological activity, and the full scope of their therapeutic applicability is still being unravelled.

Conclusion

This short commentary was intended to briefly discuss the latest advances reported in literature about the use of native herbs of Cerrado biome against neurodegenerative diseases. In this sense, it was clear that Cerrado herbs showcase remarkable antioxidant activity, which is also associated to anticholinesterase properties, thence implicating that some plants of this biome might find use in the therapeutic of neurodegenerative diseases.

Acknowledges

Author would like to thank CAPES, Brazil for the financial support.

Conflict of interest

Author declare that there is no conflict of interest.

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