Exploring the antiviral potential of justicidin B and four glycosylated lignans from Phyllanthus brasiliensis against Zika virus: A promising pharmacological approach.

BACKGROUND: Zika virus (ZIKV) is an emerging arbovirus that in recent years has been associated with cases of severe neurological disorders, such as microcephaly in newborns and Guillain-Barré syndrome in adults. As there is no vaccine or treatment, the search for new therapeutic targets is of great relevance. In this sense, plants are extremely rich sources for the discovery of new bioactive compounds and the species Phyllanthus brasiliensis (native to the Amazon region) remains unexplored. PURPOSE: To investigate the potential antiviral activity of compounds isolated from P. brasiliensis leaves against ZIKV infection. METHODS: In vitro antiviral assays were performed with justicidin B (a lignan) and four glycosylated lignans (tuberculatin, phyllanthostatin A, 5-O-ß-d-glucopyranosyljusticidin B, and cleistanthin B) against ZIKV in Vero cells. MTT colorimetric assay was used to assess cell viability and plaque forming unit assay to quantify viral load. In addition, for justicidin B, tests were performed to investigate the mechanism of action (virucidal, adsorption, internalization, post-infection). RESULTS: The isolated compounds showed potent anti-ZIKV activities and high selectivity indexes. Moreover, justicidin B, tuberculatin, and phyllanthostatin A completely reduced the viral load in at least one of the concentrations evaluated. Among them, justicidin B stood out as the main active, and further investigation revealed that justicidin B exerts its antiviral effect during post-infection stages, resulting in a remarkable 99.9 % reduction in viral load when treatment was initiated 24 h after infection. CONCLUSION: Our findings suggest that justicidin B inhibits endosomal internalization and acidification, effectively interrupting the viral multiplication cycle. Therefore, the findings shed light on the promising potential of isolated compounds isolated from P. brasiliensis, especially justicidin B, which could contribute to the drug development and treatments for Zika virus infections.

Acute toxicity study of stone-breaker (Phyllanthus tenellus Roxb)

Phyllanthus tenellus Roxb. é nativa do Brasil, mais frequentemente em ambientes úmidos, e usada para o tratamento de litíase urinária, doença inflamatória intestinal, diabetes e hepatite B. Neste trabalho objetiva-se determinar a toxicidade aguda e DL50 do extrato aquoso de P. tenellus em animais de laboratório e avaliar o seu comportamento. A DL50 por via intraperitoneal foi calculada pelo método de Karber e Behrens (1964), em que o extrato alcoólico a 96% foi concentrado em evaporador rotativo. Utilizou-se camundongos albinos (Mus musculus) machos, divididos em 3 lotes de seis animais. Eles foram observados por 24 horas a partir da administração do extrato diluído em solução fisiológica a 0,9% nas dosagens de 500; 1000; 1500; 2000; 2500 mg/kg. Estudos de curto prazo têm demonstrado que esta planta não é considerada tóxica, porém, constatamos que esta espécie provoca agitação nos animais por movimentos estereotipados, espasmos, e um aumento da frequência respiratória, bem como ações de depressão, tais como: sonolência, prostração, dispneia e diminuição da frequência respiratória.

Phyllanthus tenellus Roxb. is a herbaceous plant native to Brazil and appears frequently in humid environments. This plant is used to treat urolithiasis, inflammatory bowel disease, diabetes and hepatitis B. The acute toxicity and LD50 of an aqueous extract of P. tenellus were determined in laboratory mice and their behavior was analyzed. The intraperitoneal LD50 was calculated by the Karber & Behrens (1964) method, for which a 96% alcoholic extract was concentrated in a rotary evaporator. Male albino mice (Mus musculus) were divided into three batches of six animals and observed for 24 hours after administration of the extract, diluted in 0.9% saline, at doses of 500, 1000, 1500, 2000 and 2500 mg / kg. Short-term studies have demonstrated this plant to be non-toxic; however, we found that this species induced agitation in animals, with stereotyped movements, spasms and increased respiratory frequency, as well as signs of depression, such as sleepiness, prostration, dyspnea and a reduction in respiratory frequency.

Densidade de plantio e idade de colheita de quebra-pedra [Phyllanthus amarus (Schumach. & Thonning) genótipo Unicamp-CPQBA 14] na produtividade de filantina / Density of planting and age of Phillanthus amarus genotype UNICAMP/CPQBA-14 on the productivity of phyllanthin

Avaliou-se o efeito da densidade de plantio e da idade de Phyllanthus amarus CPQBA-14, sobre o teor e produtividade de filantina. O delineamento experimental foi em blocos ao acaso, em esquema fatorial 4 x 6, com cinco repetições, envolvendo 4 tratamentos de densidade de plantio (400.000 pl ha -1; 200.000 pl ha -1; 100.000 pl ha -1 e 66.667,68 pl ha -1) com 6 colheitas (30, 45, 60, 75, 90 e 105 dias após o transplante (DAT)). Os dados foram submetidos a Análise de Variâncias e Regressão (P > 0.001). Para o teor de Filantina, foram observados efeitos significativos e independentes dos tratamentos de idade da planta na colheita e densidade de plantio. O teor de filantina aumentou linearmente com a idade da planta, atingindo o máximo aos 105 DAT, com teor de 11,52 g Kg-1. O adensamento populacional estimado que proporcionou máximo teor de filantina (8,66 g kg-1) foi de 299.860 pl ha-1. A produtividade de filantina apresentou interação significativa entre densidade de plantio e idade da planta na colheita. Observou-se que ao longo do crescimento da planta, os tratamentos com 200 e 400.000 pl ha -1 apresentaram as maiores produtividades de filantina (39,3 e 37,8 kg ha-1) aos 97,12 e 95,17 DAT, respectivamente. Conclui-se que o espaçamento apropriado para o melhor arranjo espacial de cultivo é de 299.860 pl ha-1 para as produtividades de 3.974,19 Kg (massa de matéria seca foliar) x 0,00866 kg (teor de filantina) = 34,416 kg ha-1 de filantina, com colheita programada aos 97 DAT.

The effect of planting density and age of Phyllanthus amarus- genotype CPQBA-14, on the content and productivity of phyllanthin were evaluated. The experimental design was randomized blocks in factorial scheme 4 x 6, with five replicates, consisting of 4 treatments of planting density (400.000 pl ha-1; 200.000 pl ha-1; 100.000 pl ha-1 and 66667.68 pl ha-1) with six ages of plants (30, 45, 60, 75, 90 and 105 days after transplanting (DAT)). Data were subjected to analysis of variance and regression (P>0.005). For phyllanthin content independent and significant effects of harvest and planting density were observed. The phyllanthin contents increased with plant age, peaking at 105 DAT, with a content of 11.52 g kg-1. The estimated population density that provided the high phyllanthin contents (8.66 g kg-1) was at 299.860 pl ha-1. The productivity of phyllanthin showed significant interaction between planting density and plants ages. It was observed during the plant growth, the treatments with 200 and 400.000 pl ha -1 had the highest yield of phyllanthin (39.3 and 37.8 kg ha-1) with 95.17 and 97.12 DAT, respectively. We conclude that the proper spacing for best spatial arrangement of the cultivation is 299.860 pl ha-1 for the yield of 3974.19 kg (dry weight leaf) x 0.00866 kg (phyllanthin contents) = 34.416 kg ha-1 of phyllanthin with harvest scheduled at 97 DAT.

EFEITO DA ADUBAÇÃO ORGÂNICA NA PRODUÇÃO DE BIOMASSA EM QUEBRA-PEDRA (Phyllanthus stipulatus, EUPHORBIACEAE) EM MANAUS, AMAZONAS, BRASIL

Quebra-pedra (Phyllanthus stipulatus (Raf.) Webster, Euphorbiaceae) is a popular remedy used to reduce uric acid in blood and to facilite the elimination of kidney stones. The research was carried out at the Vegetable Crops Experiment Station of the National Institute for Amazonian Research, in Manaus, Amazonas, Brazil, using seeds of a local wild population. A split-plot design was used, where the main plots were the natural environment and 50% shade, the subplots were constituted by doses of 0,2,4,6, 8 and 10 kg of organic compost (OC)/m2 and contained 20 plants in 1 m2. The following characters of the 6 useful plants per subplot were evaluated: stalk diameter at soil level, plant height, root, stalk, branch and leaf biomass (fresh and dry). No significant differences among environments were found for total plant biomass (63.1 g vs 62.3 g fresh wt, 26.6 g vs 25.6 g dry wt, respectively), but were found for height (70.0 cm in sun light vs 96.2 cm in shade) and, consequendy, for stalk biomass (5.1 and 5.7 g dry wt, respectively). Quebra-pedra responds to organic manure, both in total biomass and in all of its components, with an increment of 43% in total biomass between the minimum and maximum treatment, but the benefit/cost ratio suggests that 4 kg of OC/m2 is the maximum amount that is economically viable in the soil used. Total biomass is composed of 17.2% root, 22.3% stalk, 23.1% branches and 37.4% leaves. Plant growth demands considerable potassium but little phosphorous, magnesium or micronutrients.

O quebra-pedra (Phyllanthus stipulatus (Raf.) Webster, Euphorbiaceae) é um importante remédio popular usado para reduzir o ácido urico no sangue e facilitar a eliminação de cálculos renais. Para avaliar a produção de biomassa dessa espécie utilizou-se sementes de populações naturais num experimento realizado em Manaus, AM. Adotou-se um delineamento experimental de parcelas subdivididas, onde as parcelas foram: (a) o ambiente natural e (b) o ambiente com tela plástica sombrite com 50% de luminosidade, e as subparcelas constituídas por dosagens de 0,2,4,6,8 e 10 kg de composto orgânico/ m2. Não foram encontradas diferenças significativas entre os ambientes na biomassa total das plantas (63,1 g vs 62,3 g fresca e 26,6 g vs 25,6 g seca), embora tivessem sido encontradas para a altura (70,0 cm a pleno sol vs 96,2 cm sombra) e, conseqüentemente, para a biomassa do caule (5,lg vs 5,7 g seca, respectivemente). O quebra-pedra responde bem a adubação orgânica, tanto na biomassa total, como em todas as partes da planta. A melhor resposta, em termos de rendimento, se deu sob o efeito de 10 kg de CO/m2 incorporado ao solo ( 1,26 kg/m2 de biomassa fresca e 0,55 kg/m2 de biomassa seca). Em comparação com a testemunha, este tratamento produziu 43% mais biomassa seca total. No entanto, a razão benefício/ custo sugere que 4 kg de CO/m2 é a quantidade máxima que é economicamente viável no solo usado. A biomassa total é composta de 17,2% de raízes, 22,3% de caules, 23,1% de galhos e 37,4% de folhas. O crescimento das plantas exige muito potássio e pouco fósforo, magnésio e micronutrientes.