Identification of an Oligostilbene, Vaticanol B, from Dryobalanops aromatica Leaves as an Antiviral Compound against the Hepatitis C Virus.

Chronic hepatitis C virus (HCV) infection can lead to liver cirrhosis and hepatocellular carcinoma. Although current medications using direct-acting antivirals (DAAs) are highly effective and well-tolerated for treating patients with chronic HCV, high prices and the existence of DAA-resistant variants hamper treatment. There is thus a need for easily accessible antivirals with different mechanisms of action. During the screening of Indonesian medicinal plants for anti-HCV activity, we found that a crude extract of Dryobalanops aromatica leaves possessed strong antiviral activity against HCV. Bioassay-guided purification identified an oligostilbene, vaticanol B, as an active compound responsible for the anti-HCV activity. Vaticanol B inhibited HCV infection in a dose-dependent manner with 50% effective and cytotoxic concentrations of 3.6 and 559.5 µg/mL, respectively (Selectivity Index: 155.4). A time-of-addition study revealed that the infectivity of HCV virions was largely lost upon vaticanol B pretreatment. Also, the addition of vaticanol B following viral entry slightly but significantly suppressed HCV replication and HCV protein expression in HCV-infected and a subgenomic HCV replicon cells. Thus, the results clearly demonstrated that vaticanol B acted mainly on the viral entry step, while acting weakly on the post-entry step as well. Furthermore, co-treatment of the HCV NS5A inhibitor daclatasvir with vaticanol B increased the anti-HCV effect. Collectively, the present study has identified a plant-derived oligostilbene, vaticanol B, as a novel anti-HCV compound.

Determination of Cassiarin A Level of Cassia siamea Leaf Obtained from Various Regions in Indonesia Using the TLC-Densitometry Method.

Cassia siamea leaf has been proven in vitro and in vivo to have a strong antimalarial activity with Cassiarin A as its active compound. To obtain a source of C. siamea medicinal plant with high level of active antimalarial compound (Cassiarin A), a valid method for determining Cassiarin A level is needed. For this reason, this research conducts the validation of the Cassiarin A content with determination method using thin-layer chromatography (TLC) densitometry which includes the determination of selectivity (Rs), linearity (r), accuracy, precision, limit of detection (LOD), and limit of quantification (LOQ). Cassiarin A was chromatographed on silica gel 60 F254 TLC plate using chloroform : ethanol (85 : 15 v/v) as a mobile phase. Cassiarin A was quantified by densitometric analysis at 368 nm. The linear regression analysis data for the calibration plots showed good linear relationship with r = 0.9995. The method was validated for precision, recovery, repeatability. The minimum detectable amount was found to be 0.0027 µg/spot, whereas the limit of quantitation was found to be 0.008 µg/spot. The results of this validation are then used to determine the Cassiarin A level of C. siamea leaf from various regions in Indonesia. Based on the results of the study, it can be concluded that the TLC-densitometry method can be used to determine level of the Cassiarin A compound with the advantages of being fast, easy, accurate, and inexpensive. In addition, it showed that C. siamea leaves from Pacitan have the highest level of Cassiarin A compared to other areas studied.

Aporphine alkaloids with in vitro antiplasmodial activity from the leaves of Phoebe tavoyana.

One new aporphine named tavoyanine A (1), along with four known aporphines laetanine (2), roemerine (3), laurolitsine (4), and boldine (5), and one morphinandienone type sebiferine (6) were isolated from the leaves of Phoebe tavoyana (Meissn.) Hook f. (Lauraceae). The isolation was achieved by chromatographic techniques, and the structural elucidation was performed via spectral methods. This paper also reports the antiplasmodial activity of roemerine (3), laurolitsine (4), boldine (5), and sebiferine (6). The results showed that 3-6 have a potent inhibitory activity against the growth of Plasmodium falciparum 3D7 clone, with IC50 values of 0.89, 1.49, 1.65, and 2.76 µg/ml, respectively.

Bioanalytical method development and validation for quantification of morachalcone A in rabbit plasma using high performance liquid chromatography.

Artocarpus champeden (A. champeden) ethanol extract has been reported as antimalarial activity and prospective to be developed as phytomedicine products. The active marker compound was identical with known prenylated chalcone compound, Morachalcone A. To further develop phytomedicine products from A. champeden especially in aspects of bioavailability and pharmacokinetic, a valid, selective and sensitive analytical method becomes important to determine morachalcone A in plasma. The aim of study was to develop and validate selectivity and sensitivity of High Performance Liquid Chromatography (HPLC) method to determine morachalcone A in rabbit plasma. This method was used a RP-18 Column (250 x 4.6 mm i.d, 5 µm), under isocratic elution and acetonitrile:water (50:50 v/v) was used as mobile phase with flow rate of 1.0ml/min. Detection was carried out at 368 nm, 4-hydroxychalcone and methanol were used as internal standard and precipitant. Results showed that this HPLC method was selective with good linearity in range of 3096.774 to 154.839ng/ml. LOD and LLOQ were 89.384 and 154.839ng/ml, respectively. The mean %different was found between 2.79 to 14.33%. Intra and inter-day precision were ≤15% and recovery from this extraction method of morachalcone A and Internal Standard were 80-120%.

Three new dihydrochalcones from the leaves of Artocarpus sericicarpus Jarrett and their activity against Plasmodium falciparum.

Three new dihydrochalcones: artoserichalcone A-C (1-3), were isolated from the leaves of Artocarpus sericicarpus. The structures of compounds were determined based on NMR spectrum (1H, 13C, and 2D) and HRESIMS spectroscopic analysis. Compounds (1) and (3) showed active antimalarial activity with IC50 values of 16.90 and 13.56 µM, respectively. Meanwhile, compound (2) with an IC50 value of 63.01 µM was categorised as a moderate antimalarial substance. The cytotoxicity against Huh7, HepG2, BHK-21, and Vero cells showed that compounds (1-3) with CC50 values > 20 µg/mL could be considered non-cytotoxic. Compounds (1-3) exhibited antimalarial activity against Plasmodium falciparum and non-toxic as an antimalarial agent.

Antiviral activities of Indonesian medicinal plants in the East Java region against hepatitis C virus.

BACKGROUND: Hepatitis C virus (HCV) is a major cause of liver disease and a potential cause of substantial morbidity and mortality worldwide. The overall prevalence of HCV infection is 2%, representing 120 million people worldwide. Current standard treatment using pegylated interferon and ribavirin is effective in only 50% of the patients infected with HCV genotype 1, and is associated with significant side effects. Therefore, it is still of importance to develop new drugs for treatment of HCV. Antiviral substances obtained from natural products, including medicinal plants, are potentially good targets to study. In this study, we evaluated Indonesian medicinal plants for their anti-HCV activities. METHODS: Ethanol extracts of 21 samples derived from 17 species of medicinal plants explored in the East Java region were tested. Anti-HCV activities were determined by a cell culture method using Huh7.5 cells and HCV strains of 9 different genotypes (1a to 7a, 1b and 2b). RESULTS: Four of the 21 samples tested showed antiviral activities against HCV: Toona sureni leaves (TSL) with 50% inhibitory concentrations (IC50) of 13.9 and 2.0 µg/ml against the HCV J6/JFH1-P47 and -P1 strains, respectively, Melicope latifolia leaves (MLL) with IC50 of 3.5 and 2.1 µg/ml, respectively, Melanolepis multiglandulosa stem (MMS) with IC50 of 17.1 and 6.2 µg/ml, respectively, and Ficus fistulosa leaves (FFL) with IC50 of 15.0 and 5.7 µg/ml, respectively. Time-of-addition experiments revealed that TSL and MLL inhibited both at the entry and post-entry steps while MMS and FFL principally at the entry step. TSL and MLL inhibited all of 11 HCV strains of all the genotypes tested to the same extent. On the other hand, FFL showed significantly weaker inhibitory activities against the HCV genotype 1a strain, and MMS against the HCV strains of genotypes 2b and 7a to a lesser extent, compared to the other HCV genotypes. CONCLUSIONS: Ethanol extracts of TSL, MLL, MMS and FFL showed antiviral activities against all the HCV genotypes tested with the exception that some genotype(s) showed significant resistance to FFL and to MMS to a lesser extent. These plant extracts may be good candidates for the development of anti-HCV drugs.

Microscopic and physicochemical evaluation of Ruta angustifolia leaves.

Background: There are thousands of species of known medicinal plants in the world. Ruta angustifolia L. has been widely used in traditional medication for jaundice and liver disease. Previous studies have shown that R. angustifolia leaves can inhibit the hepatitis C virus in Huhit culture cells, reduce the value of NS3 protein, and possess a synergistic effect in combination with antiviral drugs. Therefore, this plant is potential to be developed as a drug candidate. Characteristics of plants including microscopic, physicochemical properties, and phytochemical profiles are necessary information to ensure the quality of raw material in drug development. Objective: This study was carried out to examine the microscopic and physicochemical including the standardized parameter of R. angustifolia leaves to fulfil the quality raw materials as traditional medicine. Methods: Simplicia of R. angustifolia leaves obtained from Jombang, East Java, were observed under a microscope and determined its physicochemical properties referred to the Materia Medica Indonesia V. The TLC and HPLC profiles of extract were determined as well. Results: Microscopic analysis were conducted by transfection sections and the presence of epidermis cells, palisade, mesophyll with stomata, and Ca-oxalate crystal were found. The standard parameter obtained value of loss of drying, extractive value in water and ethanol, and ash value. The TLC and HPLC profiles of leaves extract demonstrated to contain with flavonoid, terpenoids, and alkaloids. Conclusion: Ruta angustifolia obtained from Jombang, east Java, has a specific character in microscopic analysis. The physicochemical properties analysis of R. angustifolia leaves as a raw material met the requirements according to Materia Medica Indonesia V.

Alpha-mangostin, piperine and beta-sitosterol as hepatitis C antivirus (HCV): In silico and in vitro studies.

Hepatitis C is still a serious liver case of health. Up to now the development of anti-Hepatitis C Virus (HCV) drugs is challenging, especially the development of natural material compounds as anti-HCV. In the present study, we evaluated the probability of α-mangostin, piperine, and ß-sitosterol as anti-HCV with the in silico and in vitro approaches. Molecular docking was performed between nonstructural protein 5B (NS5B, PDB ID 3FQL) with α-mangostin, piperine, and ß-sitosterol by Autodock Tools® and BIOVIA Discovery Studio®. Subsequently, molecular dynamics simulations were conducted for 200 ns, evaluating the dynamic interaction between the ligands and the viral protein NS5B. Furthermore, compound characterization at the hepatocarcinoma cell line was employed. α-Mangostin with NS5B complex demonstrated the most negative binding free energy value based on MM-PBSA calculation with a value of -9.13 kcal/mol. In vitro test showed that IC50 of α -mangostin was 2.70 ± 0.92 µM, IC50 of piperine was 52.18 ± 3.21 µM, IC50 of ß-sitosterol was >100 µM. α-Mangostin can serve as a valuable lead compound for further development of the anti-HCV.

Safety evaluation of an antimalarial herbal product from Andrographis paniculata (AS201-01) in healthy volunteers.

OBJECTIVES: Andrographis paniculata tablets (AS201-01) have previously been shown to have potent bioactivity as an antimalarial and to produce no unwanted side effects in animal models. Here, we present the phase 1 clinical trial conducted to evaluate the safety of AS201-01 tablets in healthy volunteers. METHODS: The study was a randomized, double-blind controlled cross-over, a placebo-controlled design consisting of a 4-day treatment of AS201-01 tablets. A total of 30 healthy human volunteers (16 males and 14 females) were divided into two groups, and each group was given 4 tablets, twice daily for 4 days. Group 1 received AS201-01, while group 2 received placebo tablets. Volunteers were given a physical examination before the treatment. The effects of AS201-01 on random blood glucose, biochemical, and hematological as well as urine profiles were investigated. RESULTS: There were no changes in observed parameters as a result of AS201-01 being administered. Statistical analysis showed no significant difference (p>0.05) between the test and control group regarding hematology profile, biochemical profile, and random blood glucose. Increased appetite and better sleep, which categorized as grade 1 adverse event was reported after treatment with AS201-01 tablet. CONCLUSIONS: The outcome supports our previous observation that the AS201-01 tablet, given twice a day for 4 days, is safe and nontoxic.

Effect of geranylated dihydrochalcone from Artocarpus altilis leaves extract on Plasmodium falciparum ultrastructural changes and mitochondrial malate: Quinone oxidoreductase.

Nearly half of the world's population is at risk of being infected by Plasmodium falciparum, the pathogen of malaria. Increasing resistance to common antimalarial drugs has encouraged investigations to find compounds with different scaffolds. Extracts of Artocarpus altilis leaves have previously been reported to exhibit in vitro antimalarial activity against P. falciparum and in vivo activity against P. berghei. Despite these initial promising results, the active compound from A. altilis is yet to be identified. Here, we have identified 2-geranyl-2', 4', 3, 4-tetrahydroxy-dihydrochalcone (1) from A. altilis leaves as the active constituent of its antimalarial activity. Since natural chalcones have been reported to inhibit food vacuole and mitochondrial electron transport chain (ETC), the morphological changes in food vacuole and biochemical inhibition of ETC enzymes of (1) were investigated. In the presence of (1), intraerythrocytic asexual development was impaired, and according to the TEM analysis, this clearly affected the ultrastructure of food vacuoles. Amongst the ETC enzymes, (1) inhibited the mitochondrial malate: quinone oxidoreductase (PfMQO), and no inhibition could be observed on dihydroorotate dehydrogenase (DHODH) as well as bc1 complex activities. Our study suggests that (1) has a dual mechanism of action affecting the food vacuole and inhibition of PfMQO-related pathways in mitochondria.

New tricyclic alkaloids, cassiarins G, H, J, and K from leaves of Cassia siamea.

Four new alkaloids, cassiarins G, H, J, and K (1-4) which showed moderate antiplasmodial activity against Plasmodium falciparum 3D7, were isolated from the leaves of Cassia siamea (Leguminosae) and the structures of 1-4 were elucidated by 1D- and 2D-NMR analysis and X-ray crystallographic analysis.

Acacia mangium: A promising plant for isolating anti-hepatitis C virus agents.

Background: Medicinal plants are potential resources for isolating drug candidates. Various plants have been reported to possess pharmacological effects including anti-hepatitis C activities. The current study examined the anti-hepatitis C virus (HCV) activities of Acacia mangium extracts in solvents with various polarities and further evaluated the mechanism of action of the extracts using Western blotting and combination treatment models. Methods: The leaves of A. mangium were extracted in two phases, first in ethanol and then in solvents with different polarities (n-hexane, dichloromethane, and methanol). HCV-infected Huh7it-1 cells were treated with the extracts at concentrations of 0.01, 0.1, 1, 10, 50, and 100 µg/mL. Results: The results revealed the strong anti-HCV activities of the extracts. The 50% inhibition concentrations (IC 50s) of the ethanol, n-hexane, dichloromethane and methanol extracts were of 4.6 ± 0.3, 2.9 ± 0.2, 0.2 ± 0.3, and 2.8 ± 0.2 µg/mL, respectively, and no cytotoxic effect was detected. These extracts displayed stronger effects than the positive control ribavirin. The mode of action of the ethanol extract was evaluated at 30 µg/mL, revealing that the inhibitory effect was stronger on the post-entry step than on the entry step. Western blotting revealed that the extracts decreased NS3 protein expression, indicating that virus replication was suppressed. Further evaluation illustrated that combined treatment with the ethanol extract enhanced the anti-viral activity of simeprevir. Conclusions: These results indicated that A. mangium leaves could represent sources of anti-HCV agents.

New antiplasmodial indole alkaloids from Hunteria zeylanica.

Two new indole alkaloids, bisnicalaterine D (1), consisting of an eburnane and a corynanthe type of skeletons, and nicalaterine A (2) were isolated from the bark of Hunteria zeylanica. Their structures were elucidated by various spectroscopic data such as NMR and CD spectra. A series of bisnicalaterines and nicalaterine A showed potent antiplasmodial activity against Plasmodium falciparum 3D7.

Acetylcholinesterase inhibitory activity of extract and fractions from the root of Rauvolfia serpentina(L.) Bth.ex Kurz.

OBJECTIVES: Alzheimer's disease (AD) is a degenerative brain disease characterized by confusion, behavior changes, decline in memory and cognitive skills. One of the strategies in the treatment of AD is to use acetylcholinesterase (AChE) inhibitors. The current study aims to determine the AChE inhibitory activities of the extract and fractions of the root of Rauvolfia serpentina. METHODS: Extraction was carried out by maceration method using ethanol, followed by liquid-liquid partition using n-hexane, ethyl acetate and n-butanol. Further fractionation was conducted by using vacuum liquid chromatography (VLC). The AChE inhibitory assays were performed by using Ellmann's method. Phytochemical screening was carried out by TLC method. RESULTS: The ethanolic extract of R. serpentina showed inhibition against AChE enzyme with an IC50 value of 7.46 µg/mL. The extract and fractions showed higher inhibition against butyrylcholinesterase (BChE) compared to AChE. Amongst three fractions obtained, the n-butanol fraction showed the strongest inhibition with an IC50 value of 5.99 µg/mL against AChE. VLC fractionation of the n-butanol fraction yielded 13 subfractions (VLC 1-VLC 13). Four out of 13 subfractions gave more than 80% inhibition against AChE, namely subfractions 4-7, with IC50 values ranging from 4.87 to 47.22 µg/mL. The phytochemical screening of these subfractions suggested the presence of alkaloids. CONCLUSIONS: The ethanolic extract, as well as fractions of R. serpentina root, are potential for AChE inhibitor. The alkaloid compound may be responsible for this activity.

A tablet derived from Andrographis paniculata complements dihydroartemisinin-piperaquine treatment of malaria in pregnant mice.

OBJECTIVES: The use of standard antimalarial drugs, such as dihydroartemisinin-piperaquine (DHP) for the treatment of malaria during pregnancy is limited due to the risk of teratogenicity. The alternative is therefore required although few exist. Here we show a phytopharmaceutical drug derived from Andrographis paniculata (AS201-01), which is effective as herbal antimalarial both in vitro and in vivo and may be a suitable alternative when used in complementary treatment with DHP. METHODS: Plasmodium berghei infected pregnant BALB/c mice were divided into four groups: G1 (negative control), G2 (AS201-01), G3 (DHP), and G4 (combination of DHP and AS201-01). Pheripheral blood was collected during therapy for counting parasitemia. Placental samples were analyzed for the expression of IFN-γ, TNF- α, IL-10, placental parasite counts and foetal morphology. RESULTS: Groups G4 and G3 both showed a 100% inhibition of peripheral parasitemia. However, the treatment in G4 was found to be less effective than that in G2 and G3 in preventing placental parasitemia. The G4 treatment was able to reduce the expression of IFN-γ and IL-10, whereas TNF-α was not significantly different from the control group. Foetal morphologic abnormalities were observed in all groups except G2; G4 showed lower percentage of abnormalities compared to G3 and G1. CONCLUSIONS: A combination of A. paniculata tablet (AS201-01) with DHP has the potential to reduce the toxicity of DHP in malaria treatment.

Activities of Andrographis paniculata (AS201-01) Tablet on Cox-2 and Prostaglandin Expression of Placental of Plasmodium berghei Infected Mice.

BACKGROUND: Placental malaria has ability to upregulate prostaglandin synthesis by increasing cyclooxygenase-2 (Cox-2) enzyme activity. Cox-2 and prostaglandin have a role in causing uterine contraction and therefore can cause abortion or preterm labor. Tablet AS201-01 containing the ethyl acetate fraction of Andrographis paniculata was tested in vivo on pregnant mice infected with Plasmodium berghei. AS201-01 inhibited the growth of P. berghei, increased TGF-ß expression, decreased TLR-4 expression and apoptosis index of placental tissue in P. berghei infected pregnant mice and thus prevented placental malaria complications. These effects were correlated with the decrease of Cox-2 and prostaglandin expression. METHODS: Twenty-four pregnant mice (Balb/c) were divided into 4 groups (n=6). Mice were maintained at Animal Laboratory of Institute of Tropical Disease, Universitas Airlangga, Surabaya, Indonesia in 2016. G1 were uninfected pregnant mice, G2 untreated infected pregnant mice, G3 infected pregnant mice treated with AS201-01, and G4 infected pregnant mice treated with DHP tablet. All infection groups (G2-G4) were inoculated with 1x106 of P. berghei parasite on day 9 of gestation and treated on day 11. All mice were terminated at day 15 of gestation, and placental tissue was collected. Cytokine expression of Cox-2 and prostaglandin were evaluated using immunohistochemistry. RESULTS: G3 was found to have lower Cox-2 and prostaglandin expression compared to G4 and G2, but higher compared to G1. Cox-2 and prostaglandin expression was significantly different among groups (P<0.001). CONCLUSION: This study demonstrates the ability AS201-01 tablets have to decrease Cox-2 and prostaglandin expression on placental of P. berghei infected mice and therefore eliminates the adverse effects of placental malaria.

Artocarpus sericicarpus stem bark contains antimalarial substances against Plasmodium falciparum.

OBJECTIVES: The finding of alternative medicine for malarial treatment still has become a substantial demand. The plant is one of the potential sources of drugs, among other natural sources. Artocarpus species showed great potential as the antimalarial source. This study aims to obtain active antimalarial fractions from Artocarpus sericicarpus stem bark. METHODS: Stem bark of A. sericicarpus was extracted by ultrasonic-assisted extraction method using n-hexane, dichloromethane, and methanol as solvents. Fractionation of dichloromethane extract was conducted by open column chromatography using octadecyl silica as a stationary phase and gradient acetonitrile-water as a mobile phase. The antimalarial activity was determined by lactate dehydrogenase (LDH) assay against Plasmodium falciparum 3D7 strain. RESULTS: A. sericicarpus n-hexane, dichloromethane, and methanol extracts were showed antimalarial activity with an IC50 value of >4, 2.11, and >4 µg/mL, respectively. Fractionation of dichloromethane extract was obtained 13 fractions. Seven of the 13 fractions tested showed antimalarial activity. Fraction-6 performed the highest inhibition with an IC50 value of 1.53 ± 0.04 µg/mL. Phytochemistry screening revealed that Fraction-6 contains flavonoid, polyphenol, and terpenoid compounds that can take a role in its antimalarial activity. CONCLUSIONS: A. sericicarpus contains antimalarial substances mainly in Fraction-6, which strongly inhibited the growth of P. falciparum. The flavonoid, polyphenol, and terpenoid compounds were identified in Fraction-6, which need to be further isolated to obtain and elucidate the active antimalarial compounds.

Cratoxylum sumatranum stem bark exhibited antimalarial activity by Lactate Dehydrogenase (LDH) assay.

OBJECTIVES: The antimalarial drug resistance is an obstacle in the effort to overcome malaria. The new alternative antimalarial drug became in great attention of urgent need. Current antimalarial drugs were derived from plants. Therefore, the plant is considering a potential source of new drugs. Cratoxylum sumatranum belongs to the Hypericaceae family contain xanthones and phenolic compounds, which was reported for their antimalarial activities. This study aims to determine the antimalarial activities of C. sumatranum extracts and fractions. METHODS: Cratoxylum  sumatranum stem bark (BP14-SB) collected from Balikpapan Botanical Garden in East Kalimantan, Indonesia, was extracted gradually with n-hexane, dichloromethane, and methanol by ultrasonic-assisted extraction method. All extracts were tested against Plasmodium falciparum 3D7 by lactate dehydrogenase (LDH) assay and followed by IC50 determination. The most active extract was further separated and tested for their antimalarial activities. RESULTS: The results showed that dichloromethane stem bark extract (BP14-SB-D) had the strongest inhibition of parasite growth with the IC50 value of 0.44 ± 0.05 µg/mL and moderately toxic with the CC50 value of 29.09 ± 0.05 µg/mL. Further fractionation of BP14-SB-D by open column chromatography using silica gel and gradient hexane-ethyl acetate obtained 12 fractions. LDH assay for these 12 fractions of BP14-SB-D showed that Fraction-6 (IC50 value of 0.19 ± 0.03 µg/mL) was performed the strongest inhibition of parasite growth, compared to other fractions. TLC identification showed that BP14-SB-D contains xanthone. CONCLUSIONS: The dichloromethane extract of C. sumatranum stem bark (BP14-SB-D) and Fraction-6 from this extract exhibited antimalarial activity and the potential to be developed an antimalarial substance.

Phyllanthin and hypophyllanthin, the isolated compounds of Phyllanthus niruri inhibit protein receptor of corona virus (COVID-19) through in silico approach.

OBJECTIVES: Phyllanthus niruri has been known as an immunomodulator and also reported to possess an antiviral activity against several RNA viruses, such as hepatitis B virus and hepatitis C virus by inhibiting viral entry and replication. Since the current situation of Coronavirus Disease 2019 (COVID-19) which infected among the world and caused severe disease and high morbidity, it urgently needed to find new agents against COVID-19. Therefore, in silico screening against COVID-19 receptors is carried out as an initial stage of drug discovery by evaluating the activity of phyllanthin and hypophyllanthin, an isolated from Phyllanthus niruri, in inhibiting spike glycoprotein (6LZG) and main protease (5R7Y) which play as target receptors of COVID-19. METHODS: Molegro Virtual Docker 6.0 used to determine the best binding energy through the rerank score which shows the total energy bonds calculation. RESULTS: Phyllanthin and hypophyllanthin demonstrated to possess greater binding affinity toward the COVID-19 inhibition sites than their native ligand. The rerank score of phyllanthin and hypophyllanthin are lower than the native ligands 6LZG and 5R7Y. This result indicated that phyllanthin and hypophyllanthin have a stronger interaction than the native ligands both in spike glycoprotein (entry inhibitor) and main protease (translation and replication inhibitor). CONCLUSIONS: In conclusion, phyllanthin and hypophyllanthin are predicted to have strong activity against COVID-19 through inhibiting spike glycoprotein and main protease under in silico study. Further research is needed to support the development of P. niruri as inhibitor agents of COVID-19 through bioassay studies.

Screening of anti-HIV activities in ethanol extract and fractions from Ficus fistulosa leaves.

OBJECTIVES: Human immunodeficiency virus (HIV) infection is considered as a major immunosuppressive disease linked to malignancies and other opportunistic infections. Recently, the high prevalence of HIV drug-resistant strains required a high demand for novel antiviral drug development, especially in herbal medicine approaches. The objective of this study was to evaluate the possibility of Ficus fistulosa leaves can inhibit HIV replication in ethanol extract form as well as its fractions using chloroform, ethyl acetate, and butanol solvents. METHODS: F. fistulosa leaves were extracted using ethanol as a solvent and further gradually fractionated in chloroform, ethyl acetate, and butanol solvents. The targeted persistently infected virus (MT4/HIV) cell lines were cocultured with ethanol extract and fractions at different time points. The syncytium formation and cytotoxicity assays were performed to evaluate the potential antiviral activity of F. fistulosa leaves. RESULTS: One of the four tested extract/fractions showed antiviral activity against HIV. The ethanol extract showed weak inhibition with a high level of toxicity (IC50 = 8.96 µg/mL, CC50 ≥50 µg/mL, and SI = 5.58). Meanwhile, chloroform fraction effectively inhibited the MT4/HIV cell proliferation while keeping the toxicity to a minimal level (IC50 = 3.27 µg/mL, CC50 = 29.30 µg/mL, and SI = 8.96). In contrast of ethyl acetate fraction and butanol fraction showed no anti HIV activity with a high level of toxicity (CC50 ≥50 µg/mL) and low SI value (>2.17 µg/mL and >0.97 µg/mL). CONCLUSIONS: Chloroform fraction of F. fistulosa leaves showed effectively as anti-viral activity against MT4/HIV cells.