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- Kaempferol Derivatives from Hedychium gardnerianum : Unveiling the Potential of an Invasive PlantPublication . Tavares, Wilson R.; Barreto, Maria do Carmo; Seca, Ana M. L.The therapeutic properties of plants and of their secondary metabolites are a current research topic of great interest. Considering that Hedychium species are used in folk medicine around the globe, Hedychium gardnerianum Sheppard ex Ker Gawl., an extremely aggressive invasive plant in Hawaii and in Azores, was selected and phytochemically studied in order to search for natural compounds with interesting biological activities. […].
- Uncharted Source of Medicinal Products : The Case of the Hedychium GenusPublication . Tavares, Wilson R.; Barreto, Maria do Carmo; Seca, Ana M. L.A current research topic of great interest is the study of the therapeutic properties of plants and of their bioactive secondary metabolites. Plants have been used to treat all types of health problems from allergies to cancer, in addition to their use in the perfumery industry and as food. Hedychium species are among those plants used in folk medicine in several countries and several works have been reported to verify if and how effectively these plants exert the effects reported in folk medicine, studying their essential oils, extracts and pure secondary metabolites. Hedychium coronarium and Hedychium spicatum are the most studied species. Interesting compounds have been identified like coronarin D, which possesses antibacterial, antifungal and antitumor activities, as well as isocoronarin D, linalool and villosin that exhibit better cytotoxicity towards tumor cell lines than the reference compounds used, with villosin not affecting the non-tumor cell line. Linalool and α-pinene are the most active compounds found in Hedychium essential oils, while β-pinene is identified as the most widespread compound, being reported in 12 different Hedychium species. Since only some Hedychium species have been investigated, this review hopes to shed some light on the uncharted territory that is the Hedychium genus.
- Macaronesian Plants as Promising Biopesticides against the Crop Pest Ceratitis capitataPublication . R. Tavares, Wilson; Jiménez, Ignacio A.; Oliveira, Luísa; Kuhtinskaja, Maria; Vaher, Merike; Rosa, José S.; Seca, A. M. L.; Bazzocchi, Isabel L.; Barreto, Maria do CarmoABSTRACT: Ceratitis capitata is responsible for significant economic losses in the fruit production industry, and the market lacks biopesticides that are effective but also cheaper and less contaminating, with fewer negative impacts on the environment. In this regard, the present study suggests as potential options ethanolic extracts from several Macaronesian plants, which inhibit the oviposition and are toxic to C. capitata, and whose preparation involve a non-toxic solvent (i.e., ethanol), low energy expenditure and cheap apparatus (i.e., maceration at room temperature). Among the evaluated species, the extracts of Hedychium gardnerianum, Cistus symphytifolius and Salvia canariensis are the most active (50 mg/mL), revealing an increase in C. capitata adults’ mortality from 21.15% to 27.41% after 72 h, a value statistically identical to azadirachtin (25.93%) at the recommended concentration (0.88 mg/mL). Considering the quantity and biomass available to prepare a biopesticide in the future, and the level of activity, the ethanolic extract of H. gardnerianum was fractionated and each fraction tested. The water fraction at 50 mg/mL proved to be more effective than the original extract, both in terms of mortality (57.69%), with LT50 = 72.5 h, and oviposition deterrence (83.43%), values statistically higher than those obtained by azadirachtin at 0.88 mg/mL. Analysis of this fraction by HPLC-MS/MS showed that it is mainly composed of glycosylated derivatives of quercetin and myricetin in addition to some triterpenes. These findings highlight some Macaronesian species, and in particular, the more polar fraction of H. gardnerianum ethanolic extract, as promising and ecological alternatives to conventional insecticides, for use in the integrated management of the C. capitata pest.
- A Gigante Invasora e a sua Inesperada Dádiva AtioxidantePublication . Tavares, Wilson R.A procura por novos produtos de origem natural com benefícios para a sociedade é um tema cada vez mais interessante, não só para a comunidade científica, mas também para a população em geral e para algumas indústrias. Por exemplo, na agricultura o uso excessivo ao longo dos anos de pesticidas sintéticos tem levantado muitas preocupações devido aos seus efeitos nocivos e ao impacto negativo no meio ambiente, pelo que são altamente desejadas alternativas a estes pesticidas que sejam mais ecológicas, seguras, práticas e acessíveis. Em relação à medicina, a busca por compostos bioativos com potenciais aplicações em saúde não cessa, surgindo todos os anos vários novos medicamentos com os mais variados tipos de ação: antibacteriano, anti-inflamatório, antioxidante, anti tumoral, antiviral, etc.
- Exploring the Therapeutic Potential of Artemisia and Salvia Genera in Cancer, Diabetes, and Cardiovascular Diseases: A Short Review of Clinical EvidencePublication . Tavares, Wilson; Seca, Ana; Barreto, Maria Carmo; Fukuda, TatsuyaABSTRACT: Metabolic syndrome, a cluster of metabolic disorders comprising dyslipidemia, insulin resistance, elevated blood pressure, and abdominal obesity, is a silent epidemic that may lead to outcomes such as cardiovascular disease, diabetes, and cancer. Due to the increase in the prevalence of these pathologies, the search for better treatments and more efficient drugs is imperative. Species of Artemisia and Salvia genera are excellent examples of noteworthy sources of bioactive products with health applications, their therapeutic properties being well known both in popular medicine and in the scientific community. There are reports of plant extracts or compounds from species belonging to either of these genera, which were able to combat cancer, diabetes, and cardiovascular pathologies. For instance, dihydroartemisinin (analog of artemisin extracted from Artemisia annua L.) can reduce tumor markers p53 and Ki-67 expression levels, leading to a reduction in tumor proliferation. Salvia officinalis L. has antihyperglycemic and lipid profile-improving effects since it decreases total cholesterol, glycosylated hemoglobin, fasting glucose, low-density lipoprotein cholesterol, and triglyceride levels while increasing high-density lipoprotein cholesterol levels. Clinical trials using mixtures (dried powdered plants or extracts) of known medicinal plants are recurrent in published works, in contrast with the scarce clinical trial studies with isolated compounds. Salvia miltiorrhiza Bunge. was by far the most targeted plant in the clinical trials analyzed here. Regarding clinical trials concerning Artemisia, there are more studies aiming to see its effect on diabetes, but the studies about cancer are more advanced. This review aims to give a critical summary of the most interesting and promising results from clinical trials. The abundance of studies with limited statistically significant clinical evidence hinders progress in clinical therapy. This situation demands far greater rigor from the scientific community, researchers, regulatory agencies, editors, and reviewers in conducting and publishing clinical studies.
- Origanum vulgare subsp. virens (Hoffmanns. & Link) Bonnier & Layens Essential Oils: Chemotypes and Bioactivity as Antifungal, Antifeeding and Enzyme InhibitorsPublication . Ferreira, Rui; Martins, Mariana; Santos, Vanessa; Sardinha, Duarte; Tavares, Wilson; Sabina, Samuel; Espinel, Guacimara; Barreto, Maria Carmo; Oliveira, Luísa; Cabrera, Raimundo; Castilho, Paula; Kitić, Dušanka; Šavikin, Katarina; Randjelović, MilicaABSTRACT: Essential oils (EOs) from the leaves of Origanum vulgare subsp. virens (Hoffmanns. & Link) Bonnier & Layens, representing three chemotypes—thymol-rich, carvacrol-rich, and a mixed thymol–carvacrol type—were chemically characterized and comparatively assessed for their antifungal, insecticidal, and enzyme-inhibitory activities. This integrated approach provides a comparative assessment of all three chemotypes across multiple biological models, including phytopathogenic fungi, insect bioassays, and key enzyme targets. All EOs displayed antifungal activity for the tested phytopathogenic fungi (Alternaria alternata, Botrytis cinerea, and Fusarium oxysporum) at concentrations above 0.5 mg/mL, with the thymol-rich chemotype showing the highest activity. The minimum inhibition concentration for Oidium farinosum conidial growth was determined and found to be similar for thymol and carvacrol chemotypes and lower for the terpene mixture. Insect control activity was evaluated by an antifeeding assay, where carvacrol and especially thymol chemotypes can be classified as feeding deterrents. EOs and standards revealed a weak toxicity against Ceratitis capitata, with less than 20% mortality at a concentration of 50 mg/mL, and both chemotypes were found to be ineffective in preventing egg deposition. The acetylcholinesterase (AChE) inhibition assay revealed that carvacrol had the greatest inhibitory effect on AChE, followed by EOs, and, finally, thymol. Regarding the α- and β-glucosidase (α- and β-GLU) inhibitory assays, thymol had the strongest inhibitory effect on α-GLU, while plant β-GLU was not inhibited by the standards or OEs.