Safety evaluation of aqueous extract from Eugenia uniflora leaves: Acute and subacute toxicity and genotoxicity in vivo assays

ESI(-)FT-ICR MS for the determination of best conditions for producing extract abundant in phenolic compounds from leaves of E. uniflora and FTIR-PCA as a sample screening method

E. uniflora leaves are a rich source of phenolic compounds with biological activities, including myricitrin. In this study, the chemical profile of nine extracts prepared with leaves collected in three regions (mountain, beach, and mangrove) and at three different times of the day (8 am, 1 pm, and 6 pm) was evaluated from spectra originating from ultra-high resolution mass spectrometry (Fourier transform ion cyclotron resonance, FT-ICR) coupled to electrospray ionisation (ESI). The best time of the day and location for collecting the leaves of E. uniflora used as raw materials for producing extracts and the best ethanol concentration for obtaining an extract more abundant in compounds of interest were verified. Several flavonoids and phenolic acids were detected in their deprotonated form in the regions from m/z 200 to 1200. Myricitrin ([C21H20O12-H]-, m/ztheo 463.08820), its chloride adduct ([C21H20O12+Cl]-, m/ztheo 499.06488), other myricitrin derivatives, and some tannins were the main compounds detected. Considering obtaining an extract rich in phenolic compounds, including myricitrin, the best place and time of the day to collect E. uniflora leaves is in the beach region at 1 pm. In contrast, the best ethanol concentration for extract production is 70 wt%. Therefore, extraction at 96 wt% ethanol is better for obtaining an extract more abundant in phenolic acids, although 70 wt% ethanol also extracted these compounds. FTIR-PCA models were used to check for possible similarities in the data according to collection time of the day and location. These models demonstrated an excellent solution for sample screening.

In vitro and in vivo anti-inflammatory and antiophidic effects of the extract and fraction of Eugenia uniflora

ETHNOPHARMACOLOGICAL RELEVANCE

Eugenia uniflora Linn, popularly known as 'pitanga', is a native plant endemic to Brazil that belongs to the Myrtaceae family. Its traditional use (leaves infusion) has been reported for the treatment of different diseases, including hypertension, inflammation, and as a diuretic agent. Considering the snakebite problem and the rich molecule repertoire of this herbal species, studies that evaluate its antiophidic potential are relevant for a broad social impact.

AIM OF THE STUDY

This approach aims to evaluate the anti-inflammatory and antiophidic potential in vitro and in vivo of the extract (aqueous) and a fraction (ethyl acetate) of E. uniflora leaves against Bothrops leucurus and Bothrops brazili venoms.

MATERIALS AND METHODS

Extract and fraction from E. uniflora leaves were obtained by turbo-extraction and partitioning. The cytotoxicity was assayed on normal cell lines (Vero E6 and 3T3) using the 3-methyl-[4-5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide method. The anti-inflammatory activity of the aqueous extract was analyzed in vivo in the zymosan-induced air pouch model, and the leukocytes migration and other molecular inflammatory mediators quantified (myeloperoxidase, total protein, pro-inflammatory cytokine, malondialdehyde, and glutathione). In vitro, the antiophidic effect was evaluated by the ability of the E. uniflora extract and fraction to inhibit the enzymatic action (proteolytic, phospholipase A2, and hyaluronidase) of B. leucurus and B. brazili venoms. In addition, the antiophidic action in vivo was investigated after treatment with E. uniflora extract and fraction (50, 100, and 200 mg/kg) in the B. leucurus venom-induced paw edema with an evaluation of the antiedematogenic effect and quantification of myeloperoxidase (MPO) and pro-inflammatory cytokine levels.

RESULTS

The E. uniflora leaves extract (7.8-125 mg/mL) revealed no toxicity in cell culture, but reduced MTT by 47% at the highest concentration (250 mg/mL) in Vero E6 cells. In contrast, the E. uniflora fraction (7.8-250 mg/mL) showed no cytotoxicity for both cell lines. In the air pouch model, E. uniflora leaves extract demonstrated anti-inflammatory activity, reducing cell migration, MPO activity, protein, malondialdehyde, and proinflammatory cytokines, and increased glutathione levels. Evaluating the antiophidic action in vitro, E. uniflora extract and fraction inhibited the proteolytic, phospholipase, and hyaluronidase effects of B. leucurus and B. brazili venoms at low concentrations. In addition, the extract and fraction also demonstrated in vivo antiophidic activity by reducing edema in the first 0.5 h after treatment, besides reducing MPO and pro-inflammatory cytokines levels.

CONCLUSION

E. uniflora leaves extract showed cytotoxicity only at the highest concentration while the fraction revealed no toxic effect in vitro. This approach showed for the first time that the aqueous extract and ethyl acetate fraction of E. uniflora leaves has similar antiophidic action in vitro and in vivo, with antiedematogenic and anti-inflammatory effects and the ability to inhibit the enzymatic action of B. leucurus and B. brazili venoms. Therefore, this study points to the presence of bioactive components in the leaves of E. uniflora useful for the treatment of inflammatory disorders and ophidian accidents, expanding the therapeutic potential of this herbal species.

Synergistic and Additive Effects of Herbal Medicines in Combination with Chemotherapeutics: A Scoping Review

BACKGROUND

Natural products are increasingly gaining interest as potential new drug candidates for cancer treatment. Herbal formula, which are combinations of several herbs, are primarily used in East Asia and have a long history of use that continues today. Recently, research exploring the combination of herbal formulas and chemotherapy for cancer treatment has been on the rise.

METHODS

This study reviewed research on the co-administration of herbal formulas and chemotherapy for cancer treatment. The databases PubMed, Embase, and Cochrane Library were used for article searches. The following keywords were employed: "Antineoplastic agents," "Chemotherapy," "Phytotherapy," "Herbal medicine," "Drug synergism," and "Synergistic effect." The selection process focused on studies that investigated the synergistic interaction between herbal formulas and chemotherapeutic agents.

RESULTS

Among the 30 studies included, 25 herbal formulas and 7 chemotherapies were used. The chemotherapy agents co-administered included cisplatin, 5-fluorouracil, docetaxel, doxorubicin, oxaliplatin, irinotecan, and gemcitabine. The types of cancer most frequently studied were lung, breast, and colon cancers. Most studies evaluating the anticancer efficacy of combined herbal formula and chemotherapy treatment were conducted in vitro or in vivo.

DISCUSSION

Most studies reported synergistic effects on cytotoxicity, apoptosis, and tumor growth inhibition. These effects were found to be associated with cell cycle arrest, anti-angiogenesis, and gene expression regulation. Further studies leading to clinical trials are required. Clinical experiences in East Asian countries could provide insights for future research.

Safety Investigations of Two Formulations for Vaginal Use Obtained from Eugenia uniflora L. Leaves in Female Rats

Medicinal plants have great prominence in research into the development of new medicines. Eugenia uniflora L. (Myrtaceae) is an edible and medicinal plant with economic value in the northeast region of Brazil. Several preparations from E. uniflora leaves and its fruits are employed as a source of nutrients and bioactive compounds. In this study we evaluated the preclinical toxicology of crude extract and vaginal gel obtained from the leaves of E. uniflora (5%, 10%, and 15%) aiming to provide safety for its use in the treatment of vulvovaginitis. Both formulations were applied to the vaginal cavity for 14 days. Detailed observations of the vaginal region, including pruritus, swelling, irritation, burning, pain, and vaginal secretion, as well as the estrous cycle were evaluated. On the fifth day, blood samples were obtained from the supraorbital plexus for biochemical and hematological analyses. The animals were subsequently euthanized. All animals underwent necropsy and macroscopic examination of the vaginal mucosa and reproductive system. A histological examination was also performed. No clinically significant changes were detected during the entire experimental period. All biochemical, hematological, or histopathological parameters were within the normal range for the species. The data obtained allow us to suggest that the E. uniflora vaginal formulations are safe in this experimental model.