A review on ethnomedicinally important pteridophytes of India

Soil microbial community composition and diversity in the rhizosphere of Alsophila spinulosa growing in different habitats within the Chishui Alsophila National Nature Reserve in Guizhou Province, China

The rhizosphere is considered a highly complex and dynamic ecosystem. Rhizosphere soil microorganisms influence the growth and development of plants by mediating the transformation and absorption of nutrients. In order to explore the microbial community composition and diversity of Alsophila spinulosa growing in different habitats. Rhizosphere samples were collected from four different habitats within the Chishui Alsophila National Nature Reserve in Guizhou Province, China. According to the high-throughput sequencing results of 16 s rDNA and ITS, Proteobacteria and Ascomycota were the most abundant bacterial and fungal phyla in the rhizosphere soil of all four habitats. The alpha diversity analysis indicated that two particular habitats, Buddha Rock and Botanical Garden, harbored the highest microbial richness and diversity. LEfSe analysis revealed that Buddha Rock contained the highest relative abundance of Bacteroidetes compared to the other three study areas. Meanwhile, Tiantang Gou contained the highest relative abundance of Basidiomycota. Bacterial community composition and diversity were greatly influenced by soil pH, while fungal community composition and diversity were greatly influenced by available phosphorus, organic carbon, sucrase, and urease. The results of this study provide a scientific basis for the habitat restoration of A. spinulosa, and the improvement of the structure of the A. spinulosa rhizosphere soil microbial community. Laying a theoretical foundation for the next screening of inter-root functional flora.

In silico, in vitro, and in vivo acute and sub-acute toxicity profiling of whole plant methanol extract of Equisetum diffusum D. Don from the sub-Himalayan West Bengal, India, having ethnobotanical uses

BACKGROUND

Equisetum diffusum D. Don commonly known as 'Himalayan horsetail', has been traditionally used in the treatment of back pain, bone fracture and dislocation, and arthritis by various tribal communities of India. Our previous study confirmed the anti-inflammatory efficacy of the plant through in silico, in vitro, and in vivo model studies. Therefore, the current research is focused on safety dose evaluation for the first-time of the whole-plant methanol extract (EDME) of E. diffusum through appropriate in silico, in vitro, and in vivo approaches.

METHOD

The whole plant, along with its rhizomes, was collected, and the methanol extract was prepared. The in silico ADMET study was performed to predict the pharmacokinetics profile and toxicity of all the identified phyto-compounds of EDME previously screened by GC-MS study. In vitro cytotoxicity study of EDME was performed using two cell lines: kidney (HEK293) and liver (Huh7) cell lines. The in vivo toxicity study of EDME was validated by the acute toxicity (OECD 423, 2002) and sub-acute toxicity assays (OECD 407, 2008) in the Wistar Albino rat model.

RESULTS

The in silico ADMET study of all 47 bioactives predicted good pharmacokinetic and low toxicity profiles. In vitro cytotoxicity showed higher IC50 values of EDME viz., 672 ± 15.7 μg/mL and 1698 ± 6.54 μg/mL for both kidney (HEK293) and liver (Huh7) cell lines, respectively, which were considered as low-toxic. Based on acute oral toxicity, the LD50 value of the extract was considered "non-toxic" up to a feeding range of 2000 mg/kg of body weight. The regular consumption of the extract for an extended period (28 days) was also qualified as safe based on the body and organ weight, hematological, biochemical, and histoarchitecture results in the sub-acute toxicity assay.

CONCLUSION

The detailed in silico, in vitro, in vivo (acute and sub-acute oral toxicity) studies gave us a new insight to the safety dose evaluation of Equisetum diffusum, which may serve as a reliable documentation for undertaking the experimental validation of the ethnobotanical uses of the plant which would help in the field of drug development for the treatment of inflammation related complications.

The traditional utilization, biological activity and chemical composition of edible fern species

ETHNOPHARMACOLOGICAL RELEVANCE

Ferns form an important part of the human diet. Young fern fiddleheads are mostly consumed as vegetables, while the rhizomes are often extracted for starch. These edible ferns are also often employed in traditional medicine, where all parts of the plant are used, mostly to prepare extracts. These extracts are applied either externally as lotions and baths or internally as potions, decoctions and teas. Ailments traditionally treated with ferns include coughs, colds, fevers, pain, burns and wounds, asthma, rheumatism, diarrhoea, or skin diseases (eczema, rashes, itching, leprosy).

AIM OF THE REVIEW

This review aims to compile the worldwide knowledge on the traditional medicinal uses of edible fern species correlating to reported biological activities and isolated bioactive compounds.

MATERIALS AND METHODS

The articles and books published on edible fern species were searched through the online databases Web of Science, Pubmed and Google Scholar, with critical evaluation of the hits. The time period up to the end of 2022 was included.

RESULTS

First, the edible fern species were identified based on the literature data. A total of 90 fern species were identified that are eaten around the world and are also used in traditional medicine. Ailments treated are often associated with inflammation or bacterial infection. However, only the most common and well-known fern species, were investigated for their biological activity. The most studied species are Blechnum orientale L., Cibotium barometz (L.) J. Sm., Diplazium esculentum (Retz.) Sw., Marsilea minuta L., Osmunda japonica Thunb., Polypodium vulgare L., and Stenochlaena palustris (Burm.) Bedd. Most of the fern extracts have been studied for their antioxidant, anti-inflammatory and antimicrobial activities. Not surprisingly, antioxidant capacity has been the most studied, with results reported for 28 edible fern species. Ferns have been found to be very rich sources of flavonoids, polyphenols, polyunsaturated fatty acids, carotenoids, terpenoids and steroids and most of these compounds are remarkable free radical scavengers responsible for the outstanding antioxidant capacity of fern extracts. As far as clinical trials are concerned, extracts from only three edible fern species have been evaluated.

CONCLUSIONS

The extracts of edible fern species exert antioxidant anti-inflammatory and related biological activities, which is consistent with their traditional medicinal use in the treatment of wounds, burns, colds, coughs, skin diseases and intestinal diseases. However, studies to prove pharmacological activities are scarce, and require chemical-biological standardization. Furthermore, correct botanical classification needs to be included in publications to simplify data acquisition. Finally, more in-depth phytochemical studies, allowing the linking of traditional use to pharmacological relevance are needed to be done in a standardized way.

Genus Equisetum L: Taxonomy, toxicology, phytochemistry and pharmacology

INTRODUCTION

The genus Equisetum (Equisetaceae) is cosmopolitan in distribution, with 41 recognized species. Several species of Equisetum are widely used in treating genitourinary and related diseases, inflammatory and rheumatic problems, hypertension, and wound healing in traditional medicine practices worldwide. This review intends to present information on the traditional uses, phytochemical components, pharmacological activities, and toxicity of Equisetum spp. and to analyze the new insights for further study.

METHODS

Relevant literature has been scanned and collected via various electronic repositories, including PubMed, Science Direct, Google Scholar, Springer Connect, and Science Online, from 1960 to 2022.

RESULTS

Sixteen Equisetum spp. were documented as widely used in traditional medicine practices by different ethnic groups throughout the world. A total of 229 chemical compounds were identified from Equisetum spp. with the major group of constituents being flavonol glycosides and flavonoids. The crude extracts and phytochemicals of Equisetum spp. exhibited significant antioxidant, antimicrobial, anti-inflammatory, antiulcerogenic, antidiabetic, hepatoprotective, and diuretic properties. A wide range of studies have also demonstrated the safety of Equisetum spp.

CONCLUSION

The reported pharmacological properties of Equisetum spp. support its use in traditional medicine, though there are gaps in understanding the traditional usage of these plants for clinical experiments. The documented information revealed that the genus is not only a great herbal remedy but also has several bioactives with the potential to be discovered as novel drugs. Detailed scientific investigation is still needed to fully understand the efficacy of this genus; hence, very few Equisetum spp. were studied in detail for phytochemical and pharmacological investigation. Moreover, its bioactives, structure-activity connection, in vivo activity, and associated mechanism of action ought to be explored further.

Exploring wild Aspleniaceae ferns as safety sources of polyphenols: The case of Asplenium trichomanes L. and Ceterach officinarum Willd

The forest ecosystem is a source of material resources used since ancient times by mankind. Ferns are part of different oriental systems of traditional medicine due to the phytochemical variety of their fronds, which have allowed their traditional use to be validated through ethnopharmacological studies. In Europe, different cultures have used the same fern with a wide variety of applications due to its presence in most European forests. In recent years, studies on the phytocharacterization and biological activity of the fronds of the main European ferns have been published. In this study, the presence of polyphenolic phytochemicals has been evaluated by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) in the fronds of two wild ferns together with in vitro activities in non-tumoral and human tumoral cell lines. The polyphenols were extracted from Asplenium trichomanes L. and Ceterach officinarum Willd. by cold maceration using methanol. The main phytochemicals of polyphenolic origin in the extracts of A. trichomanes and C. officinarum determined by HPLC-MS/MS were the flavonol hyperoside and the phenolic acid chlorogenic acid, respectively. This different polyphenolic nature of both extracts contributes to the divergence of the behavior experienced in the biological activities tested, but none of the extracts showed a cytotoxic or phototoxic profile in the different tested cell lines. However, the cytoprotective values in front of the H₂O₂ oxidative stress induced in the 3T3 and HaCaT cell lines position these extracts as possible candidates for future health applications.

Green Synthesis of a Novel Silver Nanoparticle Conjugated with Thelypteris glandulosolanosa (Raqui-Raqui): Preliminary Characterization and Anticancer Activity

In the last decade, the green synthesis of nanoparticles has had a prominent role in scientific research for industrial and biomedical applications. In this current study, silver nitrate (AgNO3) was reduced and stabilized with an aqueous extract of Thelypteris glandulosolanosa (Raqui-raqui), forming silver nanoparticles (AgNPs-RR). UV-vis spectrophotometry, dynamic light scattering (DLS), and scanning transmission electron microscopy (STEM) were utilized to analyze the structures of AgNPs-RR. The results from this analysis showed a characteristic peak at 420 nm and a mean hydrodynamic size equal to 39.16 nm, while the STEM revealed a size distribution of 6.64–51.00 nm with an average diameter of 31.45 nm. Cellular cytotoxicity assays using MCF-7 (ATCC® HTB-22™, mammary gland breast), A549 (ATCC® CCL-185, lung epithelial carcinoma), and L929 (ATCC® CCL-1, subcutaneous connective tissue of Mus musculus) demonstrated over 42.70% of MCF-7, 59.24% of A549, and 8.80% of L929 cells had cell death after 48 h showing that this nanoparticle is more selective to disrupt neoplastic than non-cancerous cells and may be further developed into an effective strategy for breast and lung cancer treatment. These results demonstrate that the nanoparticle surfaces developed are complex, have lower contact angles, and have excellent scratch and wear resistance.

Chemical profiling and antioxidant activity of Equisetum ramosissimum Desf. stem extract, a potential traditional medicinal plant for urinary tract infections

Background

Equisetum ramosissimum Desf. (E. ramosissimum) is a widely used traditional medicinal plant to treat urinary tract infections (UTIs) by ethnic people throughout the world. The utility of the plant in treating urinary-related disorders was evaluated against selected pathogenic bacteria which has major role in causing UTIs. Hence, the present study executed to extract phytochemicals like total phenolics and flavonoids, chemical profiling by GC–MS analysis and to test their antioxidant activity from stem extracts of E. ramosissimum. The extraction process was directed by petroleum ether, chloroform, ethyl acetate, methanol, and aqueous solvents.

Results

The GC–MS analysis yielded 24 phytoconstituents with linoleic acid, palmitic acid, nonacosane, hexahydrofarnesyl acetone, and octacosane as major compounds. Methanolic extract yielded maximum amount of phenolics (TPC) and flavonoids (TFC) with 600.02 ± 0.22 mg GAE/g and 631.38 ± 0.69 mg QE/g, respectively. Methanolic extract also exhibited notable free radical scavenging activity with an IC50 of 123.89 ± 0.73, 150.10 ± 1.02, 146.01 ± 0.54, and 63.73 ± 6.12 µg/mL for DPPH, FRAP, ABTS, and O2− assays, respectively. The minimum inhibitory concentration (MIC) required to inhibit the growth of tested pathogenic bacteria was observed in aqueous and methanolic extracts with the value being 31.25 µg/mL against R. equi and V. cholerae. As like, methanolic and petroleum ether extracts efficiently inhibited the growth of B. subtilis with the MIC of 31.25 µg/mL.

Conclusion

It was concluded that the notable effect of methanolic and aqueous extracts against the uropathogenic bacteria reported in this study supported the traditional uses of this plant in treating UTIs. The results acquired from this investigation revealed that E. ramosissimum stem extract might be considered as an interesting candidate in the development of antibacterial agent against UTIs coupled with antioxidant properties.

Effective strategy to recycle arsenic-accumulated biomass of Pteris vittata with high benefits

Recycling the arsenic-rich biomass of Pteris vittata is a critical problem during phytoremediation primarily because of the low value and high risk of arsenic-rich biomass. Nevertheless, extracts of P. vittata have been found to have a variety of bio-activities (e.g., anti-oxidation, anti-cancer, and anti-bacterial) and abundant valuable bio-active compositions (e.g., flavonoids), which might present a new solution for the recycling of P. vittata harvests. This work demonstrated a pilot-scale experiment to extract and purify the phenolic compounds from 1 t of arsenic-rich P. vittata biomass. Result showed that 47.9 kg of phenolic-rich extract with a potential value of US$908.66-8345.14 was obtained. This extract showed no acute oral toxicities (LD₅₀ > 10 g/kg), no skin irritation, and no chronic risks in the long-term skin contact exposure pathways. All of the wastes from production have been recycled and safely disposed with low cost (US$28.44), and the cost may be further reduced. The calculated benefits from this method showed a potential to provide 995-53,050 US$/hm² per year to a phytoremediation project. Therefore, this strategy could address the issue of expensive phytoremediation.