Kalanchoe sp. Extracts-Phytochemistry, Cytotoxic, and Antimicrobial Activities.

Kalanchoe species are succulents occurring in tropical regions. They have many biological and pharmacological properties. In this study, the cytotoxic and antimicrobial activities of water and dichloromethane Kalanchoe fractions obtained from ethanol extracts of three Kalanchoe species-K. daigremontiana, K. pinnata, and K. blossfeldiana were estimated. The cytotoxic effect was assessed on human cancer cell lines-ovarian SKOV-3, cervical HeLa, breast MCF-7, and melanoma A375-by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. The antimicrobial activity was estimated on selected Gram-positive and Gram-negative bacteria strains and on Candida albicans. The phytochemical analysis of selected Kalanchoe extracts was conducted by LC-QTOF-MS. The obtained results showed that the water fraction of K. blossfeldiana was active both on the tested cancer cells (IC50 values were 28.28 ± 2.76 and 32.51 ± 0.69 µg/mL on HeLa and SKOV-3, respectively) and bacteria strains (MIC values were 16 and 32 µg/mL on S. epidermidis and S. aureus, respectively). The water fraction of K. pinnata also had a significant effect on S. epidermidis and S. aureus, with MIC values of 32 and 64 µg/mL, respectively. The water fraction of K. blossfeldiana triggered a decrease in mitochondrial membrane potential (MMP) and induced cell cycle arrest in the G2/M phase in the SKOV-3 and HeLa cells. This fraction did not significantly increase cellular oxidative stress level. The DPPH and ABTS assays revealed that the water fraction of K. blossfeldiana had a strong antioxidant effect (IC50 was 9.44 ± 0.06 and 3.17 ± 0.1 µg/mL, respectively). The phytochemical analysis of the extracts of K. blossfeldiana and K. pinnata revealed the presence of at least 218 main components. The most frequently occurring were flavonol glycosides (31 metabolites), phenylpropanoids (13 metabolites), gallic acid derivatives (13 compounds), benzoic acid derived compounds (14 metabolites), and acyclic alcohol glycosides (16 compounds). In addition, proanthocyanidins were detected mainly in K. blossfeldiana. The study indicates that the water fraction of K. blossfeldiana has significant biological potential and can be further investigated towards anticancer and antimicrobial application.

In-Vitro Effect of Kalanchoe daigremontiana and Its Main Component, Quercetin against Entamoeba histolytica and Trichomonas vaginalis.

BACKGROUND: Parasitic infections represent one of the main public health problems in humans according to the WHO. Therefore, the need has arisen to find new treatments that can be used as an alternative cure to parasitosis. We aimed to investigate the in-vitro effects of the methanolic extract of Kalanchoe daigremontiana as well as its main component, quercetin against Entamoeba histolytica and Trichomonas vaginalis. METHODS: For this purpose, the in-vitro activity of the methanol extract of K. daigremontiana also its main component, quercetin, against trophozoites of E. histolytica and T. vaginalis was evaluated, using the microassay technique. Furthermore, the antioxidant activity was determined. Finally, the cytotoxic and cytoprotective capacity was determined using the hemolysis technique. RESULTS: The IC50 indicated that quercetin significantly (P < 0.05) inhibited the growth rate of the trophozoite stage of E. histolytica and T. vaginalis in comparison to the methanolic extract of K. daigremontiana (KalL). Also, quercetin significantly (P < 0.05) was a better antioxidant as compared with the positive control. In the evaluation of cytotoxicity effects, it could be observed that KalL as compared with quercetin exhibited more cytotoxicity against human erythrocytes. Quercetin significantly (P < 0.001) exhibited better cytoprotective activity compared to KalL. CONCLUSION: Both K. daigremontiana methanolic extract and quercetin alone demonstrated high antiparasitic activity against E. histolytica and T. vaginalis. However, the in-vivo efficacy of K. daigremontiana and quercetin also requires to be evaluated using an animal model.

Actividad antioxidante y antiinflamatoria en extractos hidroalcohólicos de Kalanchoe daigremontiana Raym. -Hamet & H. Perrier / Antioxidant and anti-inflammatory activity in hydroalcoholic extracts of Kalanchoe daigremontiana Raym. -Hamet & H. Perrier / Atividade antioxidante e anti-inflamatória em extratos hidroalcoólicos de Kalanchoe daigremontiana Raym. -Hamet & H. Perrier

RESUMEN Objetivo: Evaluar la actividad antioxidante y antiinflamatoria en extractos hidroalcohólicos de las partes aéreas de Kalanchoe daigremontiana Raym. -Hamet & H. Perrier. Materiales y métodos: Se obtuvieron extractos hidroalcohólicos utilizando como solventes etanol (EtOH) y metanol (MeOH) en diferentes concentraciones. Los fenoles totales y los flavonoides se cuantificaron con el método de Folin Ciocalteu y el de complejación de aluminio respectivamente. Metodología: Para determinar la actividad antioxidante en los extractos se utilizó la técnica de decoloración del radical libre DPPH¼ (2,2-difenil-1-picrilhidracilo) y para la actividad antiinflamatoria se evaluó la capacidad inhibitoria de la enzima lipoxigenasa (LOX). Resultados: El extracto etanólico al 70% presentó mayor capacidad antioxidante frente a los radicales DPPH¼ y mayor inhibición sobre la enzima lipooxigenasa como respuesta antiinflamatoria, lo cual estaría relacionado con el contenido de fenoles y flavonoides. Conclusiones: Esto sugiere que el K. daigremontiana posee propiedades antioxidantes y antiinflamatorias.

SUMMARY Aim: To evaluate the antioxidant and anti-inflammatory activity in hydroalcoholic extracts of the aerial parts of Kalanchoe daigremontiana Raym. -Hamet & H. Perrier. Materials and methods: Extracts were obtained using ethanol (EtOH) and methanol (MeOH) as solvents at different concentrations. Total phenols and flavonoids were quantified using the Folin-Ciocalteu method and the aluminum complexation reaction, respectively. Methodology: The antioxidant activity of the extracts was determined using the DPPH¼ (2,2-diphenyl-1-picrylhydracil) free radical discoloration technique, while lipoxygenase (LOX) inhibition assays were used to measure the anti-inflammatory activity. Results: The 70% ethanolic extract showed a greater antioxidant capacity against DPPH¼ and a greater inhibition of the lipoxygenase enzyme, which should be related to the overall phenols and flavonoids content, suggesting that K. daigremontiana exhibits antioxidant and anti-inflammatory properties.

RESUMO Objetivo: Avaliar a atividade antioxidante e anti-inflamatória em extratos hidroalcoólicos da parte aérea de Kalanchoe daigremontiana Raym. -Hamet & H. Perrier. Materiais e métodos: Os extratos foram obtidos usando etanol (EtOH) e metanol (MeOH) como solventes em diferentes concentrações. Fenóis e flavonóides totais foram quantificados pelo método de Folin-Ciocalteu e pela reação de complexação com alumínio, respectivamente. Metodologia: A atividade antioxidante dos extratos foi determinada pela técnica de descoloração do radical livre DPPH¼ (2,2-difenil-1-picrilidracila), enquanto ensaios de inibição da lipoxigenase (LOX) foram utilizados para medir a atividade anti-inflamatória. Resultados: O extrato etanólico 70% apresentou maior capacidade antioxidante contra DPPH¼ e maior inibição da enzima lipoxigenase, que deve estar relacionada ao teor geral de fenóis e flavonoides, sugerindo que K. daigremontiana apresenta propriedades antioxidantes e anti-inflamatórias.

Biological activities of leaf extracts from selected Kalanchoe species and their relationship with bufadienolides content.

CONTEXT: Kalanchoe species (Crassulaceae) are widely used in traditional medicine as remedies in infectious diseases and cancer treatment. OBJECTIVE: Cytotoxic and antimicrobial activities of Kalanchoe daigremontiana Raym.-Hamet & H. Perrier, K. pinnata (Lam.) Pers., and K. blossfeldiana Poelln. extracts were determined. The relationship between biological activities and the extracts bufadienolides content was also investigated. MATERIALS AND METHODS: Fresh leaves of Kalanchoe species were macerated with 95% ethanol or water. The quantitative analysis of bufadienolides in the extracts was carried out with mass spectrometry. Cytotoxicity tests were performed on human cancer cell lines - HeLa, SKOV-3, MCF-7, and A375 by MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assay and Real-Time Cell Analysis system. The microbiological study was done using a few bacteria strains (ß-hemolytic Streptococcus, Corynebacterium diphtheriae, Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus hirae, Escherichia coli) and Candida albicans. RESULTS: The K. blossfeldiana ethanol extract and K. daigremontiana water extract exhibited the most potent cytotoxic activity (IC50 < 19 µg/mL for HeLa and SKOV-3 cells). The strongest antibacterial effects showed ethanol extract of K. blossfeldiana and K. pinnata (MIC values were 8.45, 8.45, 0.25 and <33.75 µg/mL for S. aureus, S. epidermidis, and E. hirae, respectively). The highest total amount of bufadienolides was in K. daigremontiana ethanol extract. In contrast, K. blossfeldiana ethanol extract did not show the presence of these compounds. CONCLUSIONS: Kalanchoe blossfeldiana ethanol extract is a potential candidate for cancer and bacterial infection treatment. Additionally, the biological effects of Kalanchoe extracts are not dependent on the presence and amount of bufadienolides in the plant extracts.

Green synthesis of Ag nanoflowers using Kalanchoe Daigremontiana extract for enhanced photocatalytic and antibacterial activities.

The synthesis and applications of anisotropic nanostructures have attracted much attention in the last decade. The nanoflower-type structures are one of the nanomaterials with anisotropic structures most investigated because of owing to high densities of edges, corners, and stepped atoms present on their nano-petals. Here, silver nanoparticles obtained by a one-step green synthesis method using extract from Kalanchoe Daigremontiana´s leaves are reported. To identify the compounds responsible for reduction of silver ions, the functional groups present in plant extract were investigated by UV-vis and FTIR. Ag nanoparticles were characterized by UV-vis, XPS, ζ-potential, XRD, and SEM-EDS. Different solvents were used to eliminate agglomeration of the silver nanoparticles. These solvents produced nanoflower-like morphology with abundant nano-petals. This is the first report of the synthesis of Ag nanoflowers formed by green synthesis method using Kalanchoe Daigremontiana extract. The synthesized Ag nanoflowers are faced center cubic structure in nature with a petal thickness approximately of 25 nm. Photocatalytic activity of the different Ag nanostructures was evaluated through the degradation of methylene blue, where the degradation time as low as 1 min is reported. Furthermore these green synthesized Ag nanoflowers were found to show high antibacterial activity against Gram-negative bacteria Escherichia coli and Gram-positive Staphylococcus aureus.

Anti-HSV-1 and HSV-2 Flavonoids and a New Kaempferol Triglycoside from the Medicinal Plant Kalanchoe daigremontiana.

Kalanchoe daigremontiana (Crassulaceae) is a medicinal plant native to Madagascar. The aim of this study was to investigate the flavonoid content of an aqueous leaf extract from K. daigremontiana (Kd), and assess its antiherpetic potential. The major flavonoid, kaempferol 3-O-ß-d-xylopyranosyl-(1 → 2)-α-l-rhamnopyranoside (1), was isolated from the AcOEt fraction (Kd-AC). The BuOH-soluble fraction afforded quercetin 3-O-ß-d-xylopyranosyl-(1 → 2)-α-l-rhamnopyranoside (2) and the new kaempferol 3-O-ß-d-xylopyranosyl-(1 → 2)-α-l-rhamnopyranoside-7-O-ß-d-glucopyranoside (3), named daigremontrioside. The crude extract, Kd-AC fraction, flavonoids 1 and 2 were evaluated using acyclovir-sensitive strains of HSV-1 and HSV-2. Kd-AC was highly active against HSV-1 (EC50  = 0.97 µg/ml, SI > 206.1) and HSV-2 (EC50  = 0.72 µg/ml, SI > 277.7). Flavonoids 1 and 2 showed anti-HSV-1 (EC50  = 7.4 µg/ml; SI > 27 and EC50  = 5.8 µg/ml; SI > 8.6, respectively) and anti-HSV-2 (EC50  = 9.0 µg/ml; SI > 22.2 and EC50  = 36.2 µg/ml; SI > 5.5, respectively) activities, suggesting the contribution of additional substances to the antiviral activity.

New Bufadienolides Isolated from the Roots of Kalanchoe daigremontiana (Crassulaceae).

An aqueous extract from the roots of Kalanchoe daigremontiana turned out to be a rich source of bufadienolides. The existing literature data relate mainly to the aerial parts of Kalanchoe but there is no information about the metabolic profile of the roots, which are also used in traditional medicine. Our investigation concerning the roots of K. daigremontiana led to the isolation and characterization of eight new bufadienolides, namely 1ß,3ß,5ß,14ß,19-pentahydroxybufa-20,22-dienolide (1), 19-(acetyloxy)-1ß,3ß,5ß,14ß-tetrahydroxybufa-20,22-dienolide (2), 3ß-O-α-l-rhamno-pyranosyl-5ß,11α,14ß,19-tetrahydroxybufa-20,22-dienolide (3), 19-(acetyloxy)-3ß,5ß,11α,14ß-tetrahydroxybufa-20,22-dienolide (4), 3ß,5ß,11α,14ß,19-pentahydroxy-12-oxo-bufa-20,22-dienolide (5), 19-(acetyloxy)-3ß,5ß,11α,14ß-tetrahydroxy-12-oxo-bufa-20,22-dienolide (6), 19-(acetyloxy)-1ß,3ß,5ß,11α,14ß-pentahydroxy-12-oxo-bufa-20,22-dienolide (7) and 1ß-(acetyloxy)-3ß,5ß,11α,14ß,19-pentahydroxy-12-oxo-bufa-20,22-dienolide (8), together with seven known compounds: 11α,19-dihydroxytelocinobufagin (9), bersaldegenin-1-acetate (10), daigredorigenin-3-acetate (11), bersaldegenin-1,3,5-orthoacetate (12), bryotoxin B (13), bryophyllin B (14) and bersaldegenin (15). The structures were established applying extensive 1D- and 2D-NMR and MS spectroscopic analyses.

Plant Growth-Promoting Rhizobacteria Stimulate Vegetative Growth and Asexual Reproduction of Kalanchoe daigremontiana.

Certain bacterial species associate with plant roots in soil. The plant growth-promoting rhizobacteria (PGPR) stimulate plant growth and yield in greenhouse and field. Here, we examined whether application of known bacilli PGPR strains stimulated growth and asexual reproduction in the succulent plant Kalanchoe daigremontiana. Four PGPR strains B. amyloliquefaciens IN937a, B. cereus BS107, B. pumilus INR7, and B. subtilis GB03 were applied to young plantlets by soil-drenching, and plant growth and development was monitored for three months. Aerial growth was significantly stimulated in PGPR-inoculated plants, which was observed as increases in plant height, shoot weight, and stem width. The stimulated growth influenced plant development by increasing the total number of leaves per plant. Treatment with bacilli also increased the total root biomass compared with that of control plants, and led to a 2-fold increase in asexual reproduction and plantlet formation on the leaf. Collectively, our results firstly demonstrate that Bacillus spp. promote vegetative development of K. daigremontiana, and the enhanced growth stimulates asexual reproduction and plantlet formation.

Kalanchoe daigremontiana Raym.-Hamet. & H. y su potencial uso como fuente de antioxidantes y colorantes naturales / Kalanchoe daigremontiana Raym.-Hamet. & H. and its potential use as a source of natural antioxidants and colorants

Introducción: la especie Kalanchoe daigremontiana Raym.-Hamet. & H. es una planta que presenta muy poca información sobre estudios de capacidad antioxidante, a pesar de su amplio uso en la medicina tradicional, lo cual presupone una fuente potencial de sustancias bioactivas con propiedades antioxidantes. Objetivo: evaluar el potencial antioxidante de los extractos de hojas y flores de Kalanchoe daigremontiana. Métodos: los extractos de hojas y flores se obtuvieron en metanol acidulado (HCl 10 % v/v) y su capacidad antioxidante se determinó sobre la base de los métodos del radical DPPH, del catión-radical ABTS y contenido de antocianinas totales. Resultados: los extractos, tanto de hojas como flores, mostraron un potencial antioxidante promisorio (EC50= 4,2-4,4 g extracto/mmol DPPH; 1,71-2,05 mmol Trolox/kg extracto). Adicionalmente se determinó la presencia en las flores de las antocianinas delfinidina, cianidina y pelargonidina. Conclusiones: la Kalanchoe drageimontiana presentó efecto antioxidante significativo tanto en las hojas como en las flores, comparable con el mostrado por el ácido ascórbico. Se identificó de modo tentativo la presencia de delfinidina 3-O-glucósido, cianidina 3-O-glucósido y pelargonidina 3-O-glucósido en el extracto flores; por tanto la especie bajo estudio puede ser aprovechada como fuente de sustancias bioactivas para su aplicación como aditivos en la industria de alimentos, cosmética o farmacéutica.

Introduction: little information is available on the antioxidant capacity of the species Kalanchoe daigremontiana Raym.-Hamet. & H. However, its widespread use in traditional medicine points to its potential as a source of bioactive substances with antioxidant properties. Objective: evaluate the antioxidant potential of extracts from Kalanchoe daigremontiana leaves and flowers. Methods: leaf and flower extracts were obtained in acidulated methanol (HCl 10 % v/v), and their antioxidant capacity was gauged by DPPH and ABTS radical cation assay and total anthocyanin content determination. Results: both leaf and flower extracts displayed promising antioxidant potential (EC50= 4.2-4.4 g extract/mmol DPPH; 1.71-2.05 mmol Trolox/kg extract). Determination was also made of the presence of anthocyanins delphinidin, cyanidin and pelargonidin in the flowers. Conclusions: Kalanchoe drageimontiana leaves and flowers displayed significant antioxidant capacity, comparable to that of ascorbic acid. The presence of delphinidin-3-O-glucoside, cyanidin-3-O-glucoside and pelargonidin-3-O-glucoside was tentatively identified in the flower extract. Therefore, the study species may be used as a source of bioactive substances for use as additives in the food, cosmetic or pharmaceutical industry.