Exploring the Pharmacognostical and Phytochemical Profiles of Aqueous Extracts of Kalanchoe.

The use of plants for medicinal purposes has a long history, however it is desirable a continuous evaluation seeking for complementary scientific evidences for their safe application. Species within the Kalanchoe genus are often referred to as "miracle leaf" due to their remarkable healing properties. Traditionally, these plants have been used to treat infections, inflammation, and cancer. Despite their widespread use, the identification of their active components remains incomplete. This study aimed to differentiate K. crenata (KC), K. marmorata (KM), and K. pinnata (KP) by conducting detailed histochemical and phytochemical analyses, and to assess their antioxidant capabilities. The investigation revealed significant differences between the species, highlighting the variability in phenolic (PC) and flavonoid contents (FC) and their distinct antioxidant effects. The KM demonstrated the greatest results (PC: 59.26±1.53 mgEqGA/g; FC: 12.63±0.91 mgEqCQ/g; DPPH⋅ (IC50): 110.66 ug/mL; ABTS⋅+ (IC50): 26.81 ug/mL; ORAC: 9.65±0.75 mmolTE) when compared to KC and KP. These findings underscore a new reference for research within the Kalanchoe genus.

Cymbopogon citratus (DC.) Stapf, citral and geraniol exhibit anticonvulsant and neuroprotective effects in pentylenetetrazole-induced seizures in zebrafish.

ETHNOPHARMACOLOGICAL RELEVANCE: Cymbopogon citratus (DC.) Stapf (C. citratus) is consumed as an infusion in folk medicine due to its pharmacological properties and action in the central nervous system. Epilepsy is a neurological disorder that affects millions of people. Since the currently available antiepileptic drugs often cause undesirable side effects, new alternative therapeutic strategies based on medicinal plants have been proposed. AIM OF THE STUDY: This study aimed to investigate the anticonvulsant and neuroprotective effects of C. citratus essential oil (EO) and hydroalcoholic extract (E1) from its leaves, as well as of its related compounds citral (CIT) and geraniol (GER) against the effects of pentylenetetrazole (PTZ) induced seizures in zebrafish (Danio rerio). MATERIALS AND METHODS: To evaluate the anticonvulsant properties of the samples, adult animals were pre-treated (by immersion) and subsequently exposed to PTZ solution. The involvement of GABAA receptors in the antiepileptic effects was investigated by the coadministration of flumazenil (FMZ), a known GABAA receptor antagonist. Oxidative stress markers malondialdehyde (MDA), glutathione (GSH), catalase (CAT) and nitric oxide (NO) were assessed in zebrafish brain homogenates after PTZ exposure. RESULTS: All samples increased the latency time for the first seizure, which was reduced when animals were pretreated with FMZ, suggesting the involvement of GABAA receptors in the observed properties. The association between CIT and GER at the lowest concentration studied showed a synergistic effect on the anticonvulsant activity. Decreases in MDA and NO levels and increases in GSH and CAT levels in the brain of treated animals suggested the neuroprotective effect of the compounds investigated. CONCLUSIONS: Our results proved that C. citratus EO, E1, CIT and GER have anticonvulsant effects in zebrafish and could be used as a promising adjuvant therapeutic strategy for epilepsy treatment. Furthermore, zebrafish demonstrated to be an alternative animal model of epilepsy to evaluate the anticonvulsant and neuroprotective effects of C. citratus.

Anxiolytic properties of Cymbopogon citratus (DC.) stapf extract, essential oil and its constituents in zebrafish (Danio rerio).

ETHNOPHARMACOLOGICAL RELEVANCE: Cymbopogon citratus (DC.) Stapf (Poaceae) leaves is often consumed as infusion in folk medicine due to its therapeutic properties. This plant is also rich in essential oil, which has several beneficial effects to the human health. It is known that medications commonly used to treat anxiety disorders cause undesirable side effects. Thus, it is important to evaluate the anxiolytic effects of natural products from plants, such as C. citratus, as an alternative therapy to treat these disorders. OBJECTIVE: The aim of this study was to investigate the anxiolytic properties of C. citratus essential oil (EO), hydroalcoholic extract (E1), citral (CIT), geraniol (GER) and the mixture of these terpenoids, as well as its possible mechanism of action by using zebrafish as an anxiety model. METHODS: Adult zebrafish were treated (by immersion) with C. citratus EO, E1, CIT and/or GER. The anxiolytic effects were analyzed by using the light-dark test. The mechanism involved in the anxiolytic effects was further investigated by the coadministration of flumazenil (FMZ), an antagonist of GABAA receptors. The total polyphenols (phenolic and flavonoid compounds) content of E1 was determined by using spectrophotometric assays. RESULTS: All analyzed samples showed a remarkable anxiolytic effect on zebrafish in the highest concentrations, as the animals showed a preference for the light side of the tank. Furthermore, the observed effect of EO, E1, CIT and GER was reversed by pre-treatment with FMZ, suggesting that GABAergic receptors were involved in the anxiolytic effect displayed by these samples. The association between CIT and GER in the lowest studied concentrations showed an interesting synergistic behavior on anxiolytic effect observed in light-dark test. Besides, it was demonstrated that E1 was constituted by phenolic and flavonoid compounds, which could be involved in the observed effect. CONCLUSION: This work has proved that the low-cost zebrafish can be an adequate alternative as an animal model to evaluate the anxiolytic effect of C. citratus and its related compounds. Moreover, the involvement of GABAA receptors could be responsible for the effect showed by the samples. These obtained results can potentially validate the ethnopharmacological use of C. citratus as a medicinal plant for the treatment of anxiety disorders in folk medicine.

A Simple and High-yield Synthesis of Hexadecyl Ferulate and Its In Vitro Antioxidant Potential

ABSTRACT Ferulic acid (FA) is a phenolic compound with well-known antioxidant potential that can be used as a promising anti-inflammatory and anti-cancer molecule. Furthermore, it has been reported to have neuroprotective activity. One of the main problems, which limit its clinical use, is its low bioavailability when administered orally. This limitation can be circumvented by changes in their structure and/or for preparing lipid-based formulations. The aim of this study was to synthesize a derivative of FA, the hexadecyl ferulate (HF). This compound would be more susceptible to pass through blood-brain barrier (BBB) due to its lipophilic character. The HF was obtained by Steglich esterification and yielded 76.77 ± 1.35%. Its structural characterization was performed by spectroscopic methods of Fourier-transformed infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR). FTIR spectrum of HF presented two typical bands of ester group, a C=O ester stretching band at 1725 cm-1 and a C-O stretching band at 1159 cm-1. The 1H and 13C spectral data confirmed the chemical structure of HF. Regarding the 13C NMR spectrum, HF showed a chemical shift at δ 167.39 ppm which corresponded to the carbonyl carbon of the ester group. Concerning the in vitro antioxidant potential, HF had equivalent or improved scavenger activity than FA leading to IC50 values of 0.083 ± 0.009 nmol.mL-1 and 0.027 ± 0.002 nmol.mL-1 in DPPH radical scavenging and ABTS radical cation decolorization assays, respectively. Further studies are required in order to investigate the antioxidant effect of HF in biological media.

Effects of Hypericum perforatum on turning behavior in an animal model of Parkinson's disease

Parkinson's disease (PD) is an age-related neurodegenerative disorder characterized by the slow and progressive death of dopaminergic neurons in the (substantia nigra pars compact). Hypericum perforatum (H. perforatum) is a plant widely used as an antidepressant, that also presents antioxidant and anti-inflammatory properties. We evaluated the effects of H. perforatum on the turning behavior of rats submitted to a unilateral administration of 6-hydroxydopamine (6-OHDA) into the medial forebrain bundle as an animal model of PD. The animals were treated with H. perforatum (100, 200, or 400 mg/kg, v.o.) for 35 consecutive days (from the 28th day before surgery to the 7th day after). The turning behavior was evaluated at 7, 14 and 21 days after the surgery, and the turnings were counted as contralateral or ipsilateral to the lesion side. All tested doses significantly reduced the number of contralateral turns in all days of evaluation, suggesting a neuroprotective effect. However, they were not able to prevent the 6-OHDA-induced decrease of tyrosine hydroxylase expression in the lesioned striatum. We propose that H. perforatum may counteract the overexpression of dopamine receptors on the lesioned striatum as a possible mechanism for this effect. The present findings provide new evidence that H. perforatum may represent a promising therapeutic tool for PD.

A Doença de Parkinson é uma doença neurodegenerativa relacionada à idade, caracterizada pela morte lenta e progressiva de neurônios dopaminérgicos da substância negra pars compacta. O Hypericum perforatum (H. perforatum) é um fitoterápico utilizado como antidepressivo, apresentando propriedades antioxidantes, anti-inflamatórias e nootrópicas. Neste trabalho, avaliaram-se os efeitos do tratamento com H. perforatum no comportamento rotatório de ratos no modelo da doença de Parkinson induzido pela administração unilateral de 6-OHDA no feixe prosencefálico medial. Ratos Wistar machos foram tratados com H. perforatum (100, 200 ou 400 mg/kg, v.o.) por 35 dias (do 28º dia antes até o 7º dia após a lesão). As rotações ipsilaterais e contralaterais à lesão foram registradas no 7º, 14º e 21º dias após a cirurgia. As três doses de H. perforatum utilizadas reduziram o número de rotações contralaterais, indicando um possível efeito neuroprotetor da planta. Porém, o H. perforatum não impediu a redução na expressão da enzima tirosina hidroxilase no estriado lesionado, quantificada por Western blot. Propomos que o H. perforatum possa bloquear o aumento da expressão dos receptores dopaminérgicos no estriado lesionado com 6-OHDA. Entretanto, estudos adicionais são necessários para identificar o mecanismo exato pelo qual o H. perforatum reduziu o número de rotações contralaterais. Os resultados do presente estudo sugerem o H. perforatum como um potencial agente terapêutico para a doença de Parkinson.