Gen info
- Persicaria is a genus of herbaceous flowering plants in the knotweed family, Polygonaceae. Plants of the genus are known commonly as knotweed or smartweeds. It has a cosmopolitan distribution, with species occurring almost worldwide.
- Genus was segregated from Polygonum. (19)

Botany
Daynon is a twining perennial herb, reaching a height of 1 to 1.5 meters. Nodes are prominent. Stems and branches are reddish-purple, glabrous, and spineless. Leaves are alternate, ovate to oblong shape, 5 to10 centimeters long, 3 centimeters wide, midrib violet-red, upper surface of leaf with an inverted "V" shaped spot. Stipules sheath on the stem just below the petioles, membranaceous, glabrous with no cilia at the margin. (Other polygonum spp. have ciliated membranaceous stipules.) Flowers are small, white or light reddish in color, arranged in heads (capitate); inflorescence axillary. Calyx are 5, enlarging when fruiting, transparent to white. Fruits are berries, globose in shape, enclosed in the enlarged and fleshy calyx at maturity. Seeds are small, black.

Distribution
- Native to the Philippines.
- In thickets and forests at medium and higher altitudes 1,200 to 2,000 meters throughout the Philippines.
-  Native to Assam, Bangladesh, Cambodia, China, Hainan,Himalayas, India,  Japan, Jawa, Korea, Laos, Lesser Sunda Is., Malaya, Mayanmar, Nansei-shoto, Nepal, Nicobar Is.,  Sri-Lanka,  Sumatra, Taiwan,, Thailand, Tibet, Vietnam. (18)

Parts utilized:
· Entire plant.
· Collected the year round.
· Rinse, cut into pieces, sun-dry.

Constituents
- Contains hecogenin, aurantiamide , stigmastane-3,6-ione, and 25-r-spirost-4-ene-3,12-dione, which are anti inflammatory and antiallergic.
- Phytochemical screening yielded terpenoids, flavonoids, tannins, saponins and glycosides.
- Ethanol extract of aerial parts yielded nine compounds: dotriaeontanol (1), β-sitosterol (2), methyl 3,4,5-trihydroxybenzoate (3), daucosterol (4), 3,4,5-trihydroxybenzoic acid (5), quercetin (6), quercitrin (7), hyperoside (8) and 3-O-Methy-lellagic acid 4'-O-rhamnopyranoside (9). (11)
- GC-MS study of ethanol extract of whole plant for phytochemical constituents yielded mainly a triterpene compound—squalene (47.01%), and a plasticizer compound—1,2-benzenedicarboxylic acid, monon[ethylhexyl] ester (40.30%). (see study below) (15)

Properties
- Cooling, mildly acidic.
- Relieves gastrointestinal disorders, antipyretic, deobstruent, and anti-infectious.
- Anti-allergic, anti-inflammatory, antiscorbutic, tonic, vulnerary.
- Studies suggest   antibacterial, anti-inflammatory, anti-viral, gastroprotective, anti-tumor, anti-diarrheal,  antioxidant, anthelmintic, hepatoprotective properties.

Uses
Edibility
· Fruits are edible, sour tasting.
Folkloric
· Decoction of dried material: Used for dysentery, gastroenteritis, bloody stool, indigestion, hepatitis, tonsillitis, laryngopharyngitis.
· Poultice of dried material for furuncle and abscesses.
· Plant applied as poultice to abdomen for stomachaches. Plant juice used for eye maladies. Plant decoction used for eczema of the ears. (13)
· Decoction as external wash for dermatitis, eczema, pruritus.
· Poultice or decoction as external wash used for sprains, bruises, poisonous snake bites.
· In traditional Chinese medicine, used to treat ulcers, eczema, stomach aches and various inflammatory diseases. (3) Also used to treat worms and scorpion bites.
· In Nepal, veterinary use as diuretic. (4)

Studies
• Antibacterial / Antifungal: Study evaluated various leaf extracts of Persicaria chinensis for antibacterial and antifungal activities against. All leaf extracts showed antibacterial and antifungal activity against the selected pathogenic bacteria and fungi. Methanol and aqueous extracts were comparable to reference drubs amoxicillin and fluconazole. (1)
• AP-1-Targeting Anti-Inflammatory Activity / Hepatoprotective: A previous study on the bioactivity of the methanol extract of Persicaria chinensis against LPS-induced NO and PGE2 in RAW264.7 macrophages showed prevention of HCl/EtOH-induced gastric ulcers in mice. In vivo and in vitro assays showed Pc-ME significantly reduced levels of LPS-mediated proinflammatory cytokines. The Pc-ME also showed strong antihepatotoxic activity in vivo in a mouse model of LPS/D-GaIN-induced liver injury, suggesting potential as a hepatoprotective remedy. (2)
• Anti-Inflammatory: Study evaluated a methanolic extract for inhibitory mechanisms and target proteins contributing to the anti-inflammatory responses of the plant. Results showed Pc-ME may play a pivotal role as an anti-inflammatory herbal medicine by targeting Syk and Src kinases and their downstream transcription factor NF-kB. (3)
• Anti-Tumor Activity: Research from China demonstrated in vivo antitumor activity of Polygonum chinense against human hepatocellular carcinoma cell line, Bel-7404. Study suggests varieties of P. chinensis var. chinensis may produce different pure compounds with different chemopreventive abilities to treat existing cancers. (4)
• Anti-Diarrheal: Study evaluated the anti-diarrheal activities of Polygonum chinense L. A 75% ethanol extract exhibited dose dependent anti-diarrheal activities in two mouse models. Antidiarrheal effect was attributed to two components: ellagic acid and corilagin. (6)
• Gastroprotective / Leaves: Study evaluated the gastropreventive effect of aqueous leaf extract of P. chinense against ethanol-induced gastric mucosal injury in Sprague Dawley rats. Results showed the significant protective activity, ascertained by gross appearance, histology, PAS and immunochemical studies. Activity was partly attributed to preservation of gastric mucus secretions and antioxidant activity. (7)
• Cytotoxic / Antioxidant / Antimicrobial: All tested extracts showed moderate inhibition against both Gram-positive and Gram-negative bacterial and against fungal strains. The leaf extract showed moderate antioxidant activity in DPPH, lipid peroxidation, and hydrogen peroxide assays. All extracts showed moderate cytotoxicity against all five cell lines tested. (8)
• Anthelmintic / Leaves: Study evaluated leaf extracts of Persicaria chinensis for anthelmintic potency against adult earthworm Pheretima posthuma. Aqueous and methanol extracts showed good dose dependent in vitro anthelmintic activity, attributed possibly to the presence of principles like saponins and tannins. (9)
• Hepatoprotective / Leaves: Study evaluated the hepatoprotective effects of alcohol extracts of Polygonum chinense against acute liver injury model in rats induced by CCl4. Results showed hepatoprotective activity with significant decrease in ALT, AST, MDA and significant increase in SOD content. (10)
• Anti-Influenza / Leaves: Study evaluated the anti-influenza  activity of crude extracts of P. chinense and identify the antiviral metabolites and mechanisms of activity. A methanol extract showed anti-influenza virus activity with EC50 ranging from  38.4 to 55.5 µg/mL in a CPE inhibition assay. Among 8 pure metabolites isolated, ellagic acid, methyl gallate, and caffeic acid significantly inhibited  vital replication in a dose dependent manner in both plaque inhibition and  and CPE inhibition assays with EC50s ranging from 14.7 to 81.1 µg/ml and CC50 values higher than 300 µg/ml. Mode of action studies suggested that PC3 and PC7 suppress virus entry into or replication in cells, while PC8 targets influmnza viral neuraminidase, even oseltamivir-resistant one. Results suggest effective anti-influenza virus activities and a multi-targeted inhibitor of influenza A and B viruses and potential for development of a novel herbal medicine. (13)
• Comparative Biologic Activities: In a study of four Polygonum species, Polygonum chinense antioxidant capacity and phenolic content of 64.66 mmol trolox/100 g dry weight (DW) and 4.15 g gallic acid/100 g DW, respectively; all four showing significantly higher level than five dietary vegetables, fruits and spices (spring onion, broccoli, orange, carrot and ginger).  (14)
• Phytochemical Study and Biologic Activity: GC-MS study of ethanol extract of whole plant for phytochemical constituents yielded mainly a triterpene compound—squalene (47.01%), and a plasticizer compound—1,2-benzenedicarboxylic acid, monon[2ethylhexyl] ester (40.30%). All identified compounds were generally reported to have antimicrobial activity; in addition, squalene has been reported to have anticancer, antioxidant, antitumor, chemopreventive, pesticidal and sunscreen properties, while the plssticizer compound has been reported to have antioxidant and anti-inflammatory activities.(15)
• Growth Inhibition and Apoptosis / Cervical SiHa Cancer Cells: Cervical cancer is one of the most serious malignant tumors in women. Polygonum chinense extracts have shown good growth inhibition om SiHa cells.  Chromatographic analysis yielded 12 components of which seven were phenolic compounds. Two of the phenolic compounds, ellagic acid and corilagin, showed strong growth inhibition effects in SiHa cells dose-dependently, while seven of the compounds showed low inhibition on the common human HcerEpic cell. Ellagic acid and corilagin induced G2 phase cell cycle arrest by upregulating levels of  P53, Bcl-2, caspase 3, and caspase 9, while Bax was reduced. Results suggest the PHE from PC may have potential as a nutraceutical for prevention and treatment of ovarian cancer.   (16)
• Endophytic Fungi /  Antibacterial / Antioxidant / DNA Protective: Study isolated 10 endophyric fungi from P. chinense, The fungal strains were fermented  and the ethyl acetate extracts were evaluated for antimicrobial and antioxidant activities. Almost 80% of the endophytes showed antibacterial potency against one or more pathogenic bacteria. Of all strains, Penicillium  canescens showed broad-spectrum antimicrobial activity against gram positive and gram negative pathogens as well as antioxidative and DNA protective capacities. The strain Fusarium chlamydosorum showed significant anti-radical and ferric reducing capacities. Constituent analysis showed presence of sesquiterpenes (germacrene), plasticizer (phthalic acid ester) along with phenolic acids, flavonoid (quercetin) and short chain hydrocarbons. Results show P. chinense endophytes as potential sources of antimicrobial and antioxidant compounds for novel drug discovery. (17)

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