Background: The genus Stachys L. (Lamiaceae) includes about 300 species as annual or perennial herbs or small shrubs, spread in temperate regions of Mediterranean, Asia, America and southern Africa. Several species of this genus are extensively used in various traditional medicines. They are consumed as herbal preparations for the treatment of stress, skin inflammations, gastrointestinal disorders, asthma and genital tumors. Previous studies have investigated the chemical constituents and the biological activities of these species. Thus, the present review compiles literature data on ethnomedicine, phytochemistry, pharmacological activities, clinical studies and the toxicity of genus Stachys. Methods: Comprehensive research of previously published literature was performed for studies on the traditional uses, bioactive compounds and pharmacological properties of the genus Stachys, using databases with different key search words. Results: This survey documented 60 Stachys species and 10 subspecies for their phytochemical profiles, including 254 chemical compounds and reported 19 species and 4 subspecies for their pharmacological properties. Furthermore, 25 species and 6 subspecies were found for their traditional uses. Conclusions: The present review highlights that Stachys spp. consist an important source of bioactive phytochemicals and exemplifies the uncharted territory of this genus for new research studies.

Genus Stachys: A Review of Traditional Uses, Phytochemistry and Bioactivity.

The Ames test has become one of the most commonly used tests to assess the mutagenic potential of medicinal plants since they have several biological activities and thus have been used in traditional medicine and in the pharmaceutical industry as a source of raw materials. Accordingly, this review aims to report previous use of the Ames test to evaluate the mutagenic potential of medicinal plants. A database was constructed by curating literature identified by a search on the electronic databases Medline (via Pubmed), Science Direct, Scopus, and Web of Science from 1975 to April 2020, using the following terms: "genotoxicity tests" OR "mutagenicity tests" OR "Ames test" AND "medicinal plants." From the research, 239 articles were selected, including studies of 478 species distributed across 111 botanical families, with Fabaceae, Asteraceae and Lamiaceae being the most frequent. It was identified that 388 species were non-mutagenic. Of these, 21% (83/388) showed antimutagenic potential, most notable in the Lamiaceae family. The results also indicate that 18% (90/478) of the species were mutagenic, of which 54% were mutagenic in the presence and absence of S9. Strains TA98 and TA100 showed a sensitivity of 93% in detecting plant extracts with mutagenic potential. However, the reliability of many reviewed studies regarding the botanical extracts may be questioned due to technical issues, such as testing being performed only in the presence or absence of S9, use of maximum doses below 5 mg/plate and lack of information on the cytotoxicity of tested doses. These methodological aspects additionally demonstrated that a discussion about the doses used in research on mixtures, such as the ones assessed with botanical extracts and the most sensitive strains employed to detect the mutagenic potential, should be included in a possible update of the guidelines designed by the regulatory agencies.

Mutagenic potential of medicinal plants evaluated by the Ames Salmonella/microsome assay: A systematic review.

Dioscorea, consisting of over 600 species, is the most important genus in the Dioscoreaceae family; however, the practically used plants, which are commonly called yam, are restricted to a remarkably smaller number of species. Numerous studies have reported the high nutritional value of yam, particularly as an alternative source of starch and some important micronutrients. Several Dioscorea species are widely used for various medicinal purposes as well. In many studies, the bioactivities and health benefits of Dioscorea extracts and other preparations have been related to the presence of phytochemicals, which possess antioxidant properties; they are related mainly to radical-scavenging capacity in chemical assays and positive effects on the endogenous antioxidant system in cell-based and in vivo assays. Considering the increasing number of publications on this topic and the absence of comprehensive and focused review papers on antioxidant potential, this article summarizes the results of studies on the antioxidant properties of Dioscorea spp. and their relation to phytochemicals and health benefits. A comprehensive survey of the published articles has revealed that the majority of studies have been performed with plant tubers (rhizomes, roots), while reports on leaves are rather scarce. In general, leaf extracts demonstrated stronger antioxidant potential than tuber preparations. This may be related to the differences in phytochemical composition: saponins, phenanthrenes and, for some pigment-rich species (purple yams), anthocyanins are important constituents in tubers, while phenolic acids and flavonoids are characteristic phytochemicals in the leaves. The review may assist in explaining ethnopharmacological knowledge on the health benefits of Dioscorea plants and their preparations; moreover, it may foster further studies of poorly investigated species, as well as their wider application in developing new functional foods and nutraceuticals.

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Dioscorea spp.: Comprehensive Review of Antioxidant Properties and Their Relation to Phytochemicals and Health Benefits

Microspheres have been proposed for different medical applications, such as the delivery of therapeutic proteins. The first step, before evaluating the functionality of a protein delivery system, is to evaluate their biological safety. In this work, we developed chitosan/Tween 80 microspheres loaded with magnetite nanoparticles and evaluated cell damage. The formation and physical-chemical properties of the microspheres were determined by FT-IR, Raman, thermogravimetric analysis (TGA), energy-dispersive X-ray spectroscopy (EDS), dynamic light scattering (DLS), and SEM. Cell damage was evaluated by a full set of in vitro assays using a non-cancerous cell line, human erythrocytes, and human lymphocytes. At the same time, to know if these microspheres can load proteins over their surface, bovine serum albumin (BSA) immobilization was measured. Results showed 7 nm magnetite nanoparticles loaded into chitosan/Tween 80 microspheres with average sizes of 1.431 µm. At concentrations from 1 to 100 µg/mL, there was no evidence of changes in mitochondrial metabolism, cell morphology, membrane rupture, cell cycle, nor sister chromatid exchange formation. For each microgram of microspheres 1.8 µg of BSA was immobilized. The result provides the fundamental understanding of the in vitro biological behavior, and safety, of developed microspheres. Additionally, this set of assays can be helpful for researchers to evaluate different nano and microparticles.

A Full Set of In Vitro Assays in Chitosan/Tween 80 Microspheres Loaded with Magnetite Nanoparticles.

The greater yam (Dioscorea alata L.): a review of its phytochemical content and potential for processed products and biofortification

Genotoxic properties of Betonica officinalis, Gratiola officinalis, Vincetoxicum luteum and Vincetoxicum hirundinaria extracts.

Santrauka Viena iš pagrindinių priežasčių, susijusių su metabolinėmis ligomis – padidėjęs gliukozės kiekis kraujyje. Sveikatai pavojingiausia lėtinė hiperglikemija, kuri pradiniais raidos etapais būna besimptomė, tačiau per kelerius metus gali sukelti daugelio organų ir jų sistemų ilgalakius pažeidimus. Šiame tyrime atkreiptinas dėmesys į vaistinių augalų, galinčių slopinti α-gliukozidazės fermentą, paiešką. Tyrimams pasirinktos dvi Dioskorėjos (Dioscorea spp.) rūšys: kaukazinė dioskorėja (Dioscorea caucasica Lipsky) ir niponinė dioskorėja (Dioscorea nipponica Makino), auginamos Vytauto Didžiojo universiteto Kauno botanikos sodo vaistinių augalų kolekcijoje. Tikslas − nustatyti in vitro Dioskorėjos lapų ir šaknų ekstraktų slopinimo savybes α-gliukozidazės fermentui bei įvertinti antioksidacines savybes. Tyrimo metu nustatyta, kad kaukazinių ir niponinių dioskorėjų lapų ekstraktai (200 μg/ml) > 50 % slopino α-gliukozidazės fermentą, šaknų ekstaktai (200 μg/ml) pastarąjį fermentą slopino silpnai: 20,28 % kaukazinės ir 17,87 % niponinės dioskorėjos ekstraktai. Įvertintos dioskorėjos lapų ekstraktų antioksidacinės savybės, taikant kelis matavimo metodus: DPPH· ir ABTS•+ modelinėse sistemose. Pastebėta, kad tirti augaliniai ekstraktai yra gana stiprūs antioksidantai ir pakankamai efektyviai slopina hidralazių šeimos fermentą α-gliukozidazę, todėl tokie ekstraktai galėtų būti vartojami hiperglikemijos prevencijai, o taip pat ir kaip natūralūs antioksidantai.

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Vaistinių augalų paieška cukrinio diabeto prevencijai

Dioscorea caucasica Lipsky is a tertiary relict endemic plant naturally growing in the western part of the trans-Caucasus regions; it has adapted and successfully grows in the temperate region of the Baltic countries. Information about its phytochemical composition and bioactivities is rather scarce. This study reports the results of the identification of 41 compounds in D. caucasica leaf and tuber hydroethanolic extracts using UPLC-QTOF/MS. Organic acids were found in both extracts; hydroxycinnamates and flavonoids were the main phytochemicals in the leaves, while steroidal glycosides, fatty acids (mainly hydroxylated) and carbohydrates were found in the tubers. Leaf extracts inhibited enzymes in a dose-dependent manner and were remarkably stronger inhibitors of physiologically important enzymes, namely α-amylase (48.6% at 480 µg/mL), α-glucosidase (IC50 = 41.99 and 47.95 µg/mL with and without 0.1 M Na2CO3), acetylcholinesterase (45.85% at 100 µg/mL) and angiotensin-converting enzyme (IC50 = 829.7 µg/mL), most likely due to the presence of some quantified polyphenolic antioxidants. The mode of inhibition of α-glucosidase and acetylcholinesterase was assessed via kinetic studies based on Lineweaver–Burk inhibition plots. Leaf and tuber extracts acted as mixed-type and competitive inhibitors of α-glucosidase, respectively; the leaf extract demonstrated an uncompetitive inhibition mode of acetylcholinesterase. It is expected that this new knowledge of D. caucasica will serve for its valorization in developing new health beneficial ingredients for functional foods and nutraceuticals.

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Health Beneficial Phytochemicals in Dioscorea caucasica Lipsky Leaves and Tubers and Their Inhibitory Effects on Physiologically Important Enzymes

Different anatomical parts of Dioscorea nipponica Makito have been used in foods and folk medicines for their nutritional and pharmacological properties; however, the scientific data on enzyme inhibitory activities and phytochemicals in plant extracts remain rather scarce. Such information is important for expanding possible uses of plant origin preparations in nutrition. This study, using commonly applied assays, evaluated inhibitory activity of 70% ethanol extract of D. nipponica leaves and tubers against such physiologically important enzymes as α-amylase, α-glucosidase, acethylcholinesterase, and angiotensin-converting enzyme (ACE). Inhibition of α-glucosidase and acethylcholinesterase required lower leaf extract concentrations as compared with other two enzymes. The IC 50 values of α-glucosidase and α-amylase inhibition were 66.08 and 438 μg/mL, respectively, while the inhibition of ACE at 250–1250 μg/mL was from 28.02 ± 1.17% to 77.13 ± 0.78%. The mode of inhibition of α-glucosidase and acethylcholinesterase was evaluated by the kinetic studies. Leaf and tuber extracts displayed a mixed-type non-competitive mode of α-glucosidase inhibition. Phytochemical composition of extracts was determined by UPLC-QTOF/MS and HPLC-UV methods. Leaf extract was remarkably stronger enzyme inhibitor than tuber extract and it may be explained by the differences in the secondary metabolite composition. Quinic, chlorogenic acids and quercetin glycosides, which are well-known enzyme inhibitors, were the main phytochemicals in the leaf extract, while steroidal glycosides, peptides and oligomeric sugars were the major constituents in the tuber extract. It is expected that new knowledge on D. nipponica will serve for its valorisation in developing new health beneficial ingredients for functional foods and nutraceuticals. • Phytochemicals & enzyme inhibitory activity of Dioscorea nipponica extracts reported. • Quinic, chlorogenic acids & quercetin glycosides the main leaf secondary metabolites. • Phenolics-rich leaf extract was remarkably stronger inhibitor of enzymes. • Kinetics studies explain the mode of glucosidase & acethylcholinesterase inhibition. • The relation between the identified phytochemicals and enzyme inhibition is discussed. 

Aušra Adomėnienė

Papers

Dioscorea spp.: Comprehensive Review of Antioxidant Properties and Their Relation to Phytochemicals and Health Benefits

Genotoxic properties of Betonica officinalis, Gratiola officinalis, Vincetoxicum luteum and Vincetoxicum hirundinaria extracts.

Vaistinių augalų paieška cukrinio diabeto prevencijai

Health Beneficial Phytochemicals in Dioscorea caucasica Lipsky Leaves and Tubers and Their Inhibitory Effects on Physiologically Important Enzymes

Enzyme inhibitory activity of Dioscorea nipponica Makito hydroethanolic extracts of leaves and tubers in relation to their major secondary metabolites