Absolute oral bioavailability and possible metabolic pathway of panduratin A from Boesenbergia rotunda extract in beagle dogs.

CONTEXT: Attempts are ongoing to develop medications to fight against the COVID-19 pandemic. Our previous study revealed the in vitro anti-SARS-CoV-2 activity of fingerroot [Boesenbergia rotunda (L.) Mansf. (Zingiberaceae)] and its phytochemical, panduratin A. OBJECTIVE: To investigate the pharmacokinetic profiles of panduratin A as a pure compound and in a fingerroot extract formulation in beagle dogs. MATERIALS AND METHODS: A total of 12 healthy dogs were randomly divided into three groups, a single dose of 1 mg/kg panduratin A by intravenous and multiple doses of 5 and 10 mg/kg panduratin A fingerroot extract formulation by oral administration for seven consecutive days. The plasma concentration of panduratin A was determined by LCMS. RESULTS: The peak concentrations of a single dose of 5 and 10 mg/kg panduratin A fingerroot extract formulation were 12,416 ± 2,326 and 26,319 ± 8,221 µg/L, respectively. Increasing the oral dose of fingerroot extract formulation, equivalent to panduratin A 5-10 mg/kg, showed dose proportionality, with an approximately 2-fold increase in Cmax and AUC. The absolute oral bioavailability of panduratin A in the fingerroot extract formulation was approximately 7-9%. The majority of panduratin A was biotransformed into several products via oxidation and glucuronidation, and predominantly excreted via the faecal route. CONCLUSION: The oral formulation of fingerroot extract was safe in beagle dogs, and increasing dose showed dose proportionality in terms of the systemic exposure of panduratin A. This information will support the phytopharmaceutical product development of fingerroot extract against the COVID-19 pandemic.

Genome Assembly and Analysis of the Flavonoid and Phenylpropanoid Biosynthetic Pathways in Fingerroot Ginger (Boesenbergia rotunda).

Boesenbergia rotunda (Zingiberaceae), is a high-value culinary and ethno-medicinal plant of Southeast Asia. The rhizomes of this herb have a high flavanone and chalcone content. Here we report the genome analysis of B. rotunda together with a complete genome sequence as a hybrid assembly. B. rotunda has an estimated genome size of 2.4 Gb which is assembled as 27,491 contigs with an N50 size of 12.386 Mb. The highly heterozygous genome encodes 71,072 protein-coding genes and has a 72% repeat content, with class I TEs occupying ~67% of the assembled genome. Fluorescence in situ hybridization of the 18 chromosome pairs at the metaphase showed six sites of 45S rDNA and two sites of 5S rDNA. An SSR analysis identified 238,441 gSSRs and 4604 EST-SSRs with 49 SSR markers common among related species. Genome-wide methylation percentages ranged from 73% CpG, 36% CHG and 34% CHH in the leaf to 53% CpG, 18% CHG and 25% CHH in the embryogenic callus. Panduratin A biosynthetic unigenes were most highly expressed in the watery callus. B rotunda has a relatively large genome with a high heterozygosity and TE content. This assembly and data (PRJNA71294) comprise a source for further research on the functional genomics of B. rotunda, the evolution of the ginger plant family and the potential genetic selection or improvement of gingers.

Phytochemicals of Zingiberaceae family exhibit potentiality against SARS-CoV-2 main protease identified by a rational computer-aided drug design.

Coronavirus disease 2019 (COVID-19) has created huge social, economic and human health crises globally. Discovery of specific drugs has become a new challenge to the researcher. Structure-based virtual-screening of our in-house databank containing1102 phytochemicals of Zingiberaceae family was performed with main protease(Mpro), a crucial enzyme of SARS-CoV-2. Rigorous docking and ADME study of top-scored twenty hits resulted from VS was performed. Then 100 ns molecular dynamics followed by MMPBSA binding free energy(ΔGbind) calculation of A280 and KZ133 was also performed. These two hits showed good interactions with crucial amino acid residues of Mpro HIS-41 and CYS-145, excellent ADME properties, fair ΔGbind values (> ‒188.03 kj/mol), and average protein-ligand complex RMSD < apo-protein RMSD. Therefore, the seed extracts of Alpinia blepharocalyx and rhizome extracts Kaempferia angustifolia containing A280 and KZ133, respectively, may be useful against COVID-19 after the proper biological screening. These two novel scaffolds could be exploited as potent SARS-CoV-2-Mpro inhibitors.

High-content screening of Thai medicinal plants reveals Boesenbergia rotunda extract and its component Panduratin A as anti-SARS-CoV-2 agents.

Since December 2019, the emergence of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has caused severe pneumonia, a disease named COVID-19, that became pandemic and created an acute threat to public health. The effective therapeutics are in urgent need. Here, we developed a high-content screening for the antiviral candidates using fluorescence-based SARS-CoV-2 nucleoprotein detection in Vero E6 cells coupled with plaque reduction assay. Among 122 Thai natural products, we found that Boesenbergia rotunda extract and its phytochemical compound, panduratin A, exhibited the potent anti-SARS-CoV-2 activity. Treatment with B. rotunda extract and panduratin A after viral infection drastically suppressed SARS-CoV-2 infectivity in Vero E6 cells with IC50 of 3.62 µg/mL (CC50 = 28.06 µg/mL) and 0.81 µΜ (CC50 = 14.71 µM), respectively. Also, the treatment of panduratin A at the pre-entry phase inhibited SARS-CoV-2 infection with IC50 of 5.30 µM (CC50 = 43.47 µM). Our study demonstrated, for the first time, that panduratin A exerts the inhibitory effect against SARS-CoV-2 infection at both pre-entry and post-infection phases. Apart from Vero E6 cells, treatment with this compound was able to suppress viral infectivity in human airway epithelial cells. This result confirmed the potential of panduratin A as the anti-SARS-CoV-2 agent in the major target cells in human. Since B. rotunda is a culinary herb generally grown in China and Southeast Asia, its extract and the purified panduratin A may serve as the promising candidates for therapeutic purposes with economic advantage during COVID-19 situation.

Aframomum melegueta secondary metabolites exhibit polypharmacology against SARS-CoV-2 drug targets: in vitro validation of furin inhibition.

COVID-19 pandemic is currently decimating the world's most advanced technologies and largest economies and making its way to the continent of Africa. Weak medical infrastructure and over-reliance on medical aids may eventually predict worse outcomes in Africa. To reverse this trend, Africa must re-evaluate the only area with strategic advantage; phytotherapy. One of the many plants with previous antiviral potency is against RNA viruses is Aframomum melegueta. In this study, one hundred (100) A. melegueta secondary metabolites have been mined and computational evaluated for inhibition of host furin, and SARS-COV-2 targets including 3C-like proteinase (Mpro /3CLpro ), 2'-O-ribose methyltransferase (nsp16) and surface glycoprotein/ACE2 receptor interface. Silica-gel column partitioning of A. melegueta fruit/seed resulted in 6 fractions tested against furin activity. Diarylheptanoid (Letestuianin A), phenylpropanoid (4-Cinnamoyl-3-hydroxy-spiro[furan-5,2'-(1'H)-indene]-1',2,3'(2'H,5H)-trione), flavonoids (Quercetin, Apigenin and Tectochrysin) have been identified as high-binding compounds to SARS-COV-2 targets in a polypharmacology manner. Di-ethyl-ether (IC50 = 0.03 mg/L), acetone (IC50 = 1.564 mg/L), ethyl-acetate (IC50 = 0.382 mg/L) and methanol (IC50 = 0.438 mg/L) fractions demonstrated the best inhibition in kinetic assay while DEF, ASF and MEF completely inhibited furin-recognition sequence containing Ebola virus-pre-glycoprotein. In conclusion, A. melegueta and its secondary metabolites have potential for addressing the therapeutic needs of African population during the COVID-19 pandemic.