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Family Salviniaceae
Giant salvinia
Salvinia molesta D.S.Mitch.
KARIBA WEED
Ren yan huai ye ping

Scientific names Common names
Salvinia adnata Desv.            African payal (Engl.)
Salvinia molesta D.Mitch.            African pyle (Engl.)
  Aquarium watermoss (Engl.)
  Azolla (Engl.)
  Giant azolla (Engl.)
  Giant salvinia (Engl.)
  Kariba weed (Engl.)
  Salvinia (Engl.)
  Salvinia moss (Engl.)
  Water spangle (Engl.)
Salvinia molesta is an accepted species. KEW: Plants of the World Online

Other vernacular names
CHINESE: Ren yan huai ye ping, Ren yan huai cai pin.
DUTCH: Grote vlotvaren.
FRENCH: Salvinia geante, Salvinie auriculee, Salvinie massive.
GERMAN: Bueschelfarn, Lästiger schwimmfarn.
INDONESIAN: Kiambang.
PORTUGUESE: Murure-carrapatinho.
SWEDISH: öronsimbräken.

Gen info
- Salvinia molesta has been reported as occasionally escaping from cultivation in Taiwan. It is a very aggressive weed of hybrid origin that has been declared a noxious weed and banned from cultivation in many countries. Biological control using a weevil has been successful in some areas (R. C. Moran, Fiddlehead Forum 19: 26-28. 1992).

Botany
Floating fronds: lamina oblong to obovate or orbicular, ca. 2.5 × 2.4-3 cm, base rounded or cordate, apex emarginate, flat or often infolded along costa, surface abaxially with sparse pale multicellular hairs, adaxially densely papillate, papillae cylindrical, ca. 1.5(-2) mm, terminated by (2-)4 setae incurved and joined at their tips; submersed frond to 12 cm. Sporocarps in long chains of up to 55, ca. 1 mm in diam., microsporangia up to 53, megasporangia 2(or 3), more densely hairy; most sporangia empty, spores if present deformed. (Flora of China)

Distribution
- Introduced.
- Naturalized.
- Native to Argentina and Brazil.

- Grown as an aquarium plant, now widely naturalized and invasive.
- Declared a noxious weed in many countries and banned from cultivation.

Invasiveness
- Salvinia molesta is one of the most serious plant management problems in the world. It reduces the concentration of nutrients and oxygen, raises CO2 and hydrogen sulfide concentrations of water leading to decreased water quality. (6)
- In nutrient rich waters it may reach a density of 30,000 small plants per m2 and can double its biomass in 2 days. (3)

- Dense mats of giant salvinia interfere with rice cultivation, clog fishing nets, disrupt water access for humans and livestock, wildlife, recreation, transportation, irrigation, hydroelectric generation, and flood control. (6)
- Infestation can reach up to 400 tonnes of wet weight per hectare. (9)
- Failed attempts at control by chemical and mechanical method may lead to environmental consequences by introduction of chemicals and  bioagents into the ecosystem.

Constituents
- Phytochemical screening of leaf extracts yielded alkaloids, tannins, and saponins in significantly high ranges. Total phenolic content was 9.84 mg GA equivalents/g and total flavonoid contents was 10.89 mg quercetin equivalentw (QE)/g. (see study below) (4)
- GC-MS analysis of ethanol leaf extract  revealed the presence of bioactive components such as apiol, hexadecanoic acid, pentadecanoic acid and octadecatriene etc. (see study below) (5)
- Phytochemical analysis yielded carbohydrates, proteins, tannin, carotenoids, alkaloids, flavonoids, terpenoids, saponin, and phenol. (6)
- Study for fresh water fern isolated two glycosides, 6'-O-(3,4-dihydroxy benzoyl)-beta-D-glucopyranosyl ester (1), and 4-O-beta-d-glucopyranoside-3-hydroxy methyl benzoate (2), along with five known compounds methyl benzoate (3), hypogallic acid (4), caffeic acid (5), paeoniflorin (6) and pikuroside (7). (7)
- Study of aqueous methanol extract isolated one new glucopyranose derivative 6'-O-(3,4-dihydroxybenzoyl)-4'-O-(4-hydroxybenzoyl)-α/β-D-glucopyranoside (1) and four known glycosides. (see study below) (8)
- Column chromatography of active fractions of fern extract for phenolic compounds yielded ascorbic acid, quercetin, gallic acid, resorcinol, catechol, vanillin, and benzoic acid. (see study below) (9)
- Crude protein content of S. molesta is relatively high in all stages of growth (32.2% young, 37.5% medium, and 36.8% mature) compared to terrestial forages. Lignin content is high as 13.7%, average crude ash 17.3%, and crude fiber 35r.2%, while tannin content increased as the plant matures (Moozhiyil and Pallauf). (9)
- Bioactive-guided fractionation of ethanol extract isolated 50 compounds. Of the six new compounds (1-6), salvinio (1) and salviniside I (2) and salviniside II (3) are novel benzofuran glucose conjugates. (see study below) (10)
- Quantitative analysis of S. molesta extract yielded phenol 7.803, flavonoid 121.41, tannin 46.154, saponin 13.12, alkaloid 1.74. (see study below)

Properties
- Invasiveness.
- Studies have suggest antibacterial, antioxidant, urease inhibitory, phytoremediative, cytotoxicity, antitumor, immunomodulatory properties.

Parts used
Leaves.

Uses

Folkloric
- No reported folkloric medicinal use in the Philippines.
Others
- Potential uses: Floating aquatic weeds have been used for mulch, compost, fodder, paper making, handicrafts, and bio-gas
generation. An impediment to commercial use is salvinia's high water content, up to 90%. (3)
- Phytoremediation: Species has phytoremediation potential because it accumulates chromium, and absorbs nitrogen and phosphorus.

Studies
Antioxidant / Leaves:
Study evaluated the antioxidant activity of leaf extracts of Salvinia molesta. Among the solvent extracts,  the ethanol extract showed maximum antioxidant activity by DPPH assay (90.3%). (see constituents above) (4)
Antibacterial / Leaves: Study evaluated the antibacterial activity of various leaf extracts against selected pathogens viz., Pseudomonas aeruginosa, Aeromonas hydrophila, Escherichia coli, Bacillus cereus, B. subtilis, and Staphylococcus aureus. The ethanolic extract showed highest activity against Pseudomonas aeruginosa followed by Aeromonas hydrophila. (see constituents above) (5)
Antioxidant / Urease Inhibitory Activity: Study of aqueous methanol extract isolated one new glucopyranose derivative 6'-O-(3,4-dihydroxybenzoyl)-4'-O-(4-hydroxybenzoyl)-α/β-D-glucopyranoside (1) and four known glycosides were identified. Compound 1 exhibited promising antioxidant potential with IC50 of 48.2, 60.3, 42.1 µM against DPPH, superoxide radical, and oxygen burst, respectively. Jack bean urease inhibition assay showed IC50 of 99.1 µM. Compound 1 is a mixed-type inhibitor of urease with a Ki value of 91.8 µM. Results suggested further studies through animal models for its potential against oxidative stress phosphodiesterase-II and urease-induced pathologies. (8)
Phenolic Compounds / Natural Antioxidants: Column chromatography of active fractions of fern extract for phenolic compounds yielded ascorbic acid, quercetin, gallic acid, resorcinol, catechol, vanillin, and benzoic acid. Study suggests the plant is a potential source of natural antioxidants that can be used as lead candidate for synthesis of antioxidant drugs for use in the treatment of many oxidative stress related diseases. (9)
Cytotoxicity Against Human Tumor Cells: Bioactive-guided fractionation of ethanol extract isolated 50 compounds. Of the six new compounds (1-6), salvinio (1) and salviniside I (2) and salviniside II (3) are novel benzofuran glucose conjugates. Sixteen abietane diterpenes (1, 7-17, and 19-22) exhibited invitro activities against human tumor cells and 7 and 8 showed selective cytotoxicity to tumor cells over normal cells. (10)
Immunomodulatory: Study evaluated the immunomodulatory efficacy of S. molesta ethanol leaf extracts in P. aeruginosa challenged freshwater crab, Oziotelphusa senex senex. Both male and female infected crab groups showed significant increase in LPO while extract treated group showed a decrease in LPO levels. Results suggest remarkable pharmacological and therapeutic effects and can act as a potent immunomodulatory agent. (11)
Silver Nanoparticles / Antibacterial / Leaves: Study reports on the economic, ecofriendly, and simple green route for rapid biosynthesis of silver nanoparticles using aqueous leaf extract as bioreductant and stabilizing agent. The synthesized AgNPs were showed antibacterial efficacy against both Gram positive and Gram negative bacteria. (12)
Phytoremediation of Wastewater / Review: Among aquatic plants, Salvinia molesta and Pistia stratiotes have been widely use for the treatment of agricultural, domestic and industrial wastewater. The wide application of these plants is due to availability, resilience in toxic environment, bioaccumulation potentials, invasive mechanism and biomass potentials. Both possess high amounts of biomass compounds making them suitable candidates for bioenergy generation.Studies are suggested for remediation of radioactive, nanoparticle, pahrmaceutical, and polymer base wastewater. (13)
Phytoremediation of Cirpofloxacin Contaminated Water: Study evaluated the toxicological safety of ciprofloxacin-contaminated water treated with Salvinia molesta for 96h. Neotropical catfish Rhamdia quelen was used as model for potential of mitigating drug accumulation in fishes. Fish exposed to Cipro (1 and 10 µg.L) in untreated water showed toxic responses with alterations in hematological, biochemical, histopathological biomarkers and accumulation of Cipro in muscles at high concentrations high for human consumption (target quotient >1). Fish exposed to water treated with S. molesta showed no toxic effect and no accumulation of Cipro in their tissues. S. molesta removed up to 97% of Cipro from the water. The decrease of Cipro from water prevented to toxic effects of Cipro on R. quelen fish and prevented antimicrobial accumulation in fish flesh. Study showed potential of phytoremediation as an efficient nature-based solution to prevent environmental toxicological effects of antimicrobials to nontarget organisms such as fish and humans, and also helps combat antimicrobial resistance. (14)
Potential Air-Retaining Ability and Thermal Insulating Effect for Fabrics Inspired by S. molesta: The plant leaf of S. molesta can retain an air layer underwater due to the hydrophobic and elastic eggbeater-shaped hairs on its surface, which have potential applications in thermal insulation devices. Air volume change and thermal insulation tests showed that terry fabrics (F1 and F3) can retain an air layer on their surfaces and hold air in between the fibers and inside the loops underwater for a long time, providing both thermal insulation and buoyancy force – the two key features of life-saving appliances. (15)
Phytoremediation of Arsenite Contaminated Water / Role of Antioxidant Enzymes: Study tested the hypothesis that S. molesta counteracts the harmful arsenite (ASIII) effects by activating scavenging reactive oxygen species (ROS) enzymes. Study evaluated the role of superoxide dismutase (SOD), catalase (CAT), peroxidase (POX) and ascorbate peroxidase (APX) in S. molesta tolerance to arsenite and its used in the remediation of contaminated water. Results showed S. molesta presents enzymatic antioxidant defenses to alleviate arsenite toxicity and are more effective in floating leaves. Additional studies exposing plants to more prolonged stress using arsenite concentrations closer to those found in contaminated environments. (16)
Cosmeceutical Solid Soap Potential: Study evaluated the potential of this invasive species as a cosmeceutical soap product and analyzed quality, safety, and acceptance. The pH was 10.68 and moisture content of S. molesta soap was 20.01 (standard commercial soap 10.53 and 9.05 respectively). Foam height was higher. The values of S. molesta soap extracts attributes were within the limits set by standard quality of soap. The presence of S. molesta extracts in solid soap provides antibacterial potential with excellent ability to clean and disinfect skin. Results suggest an alternative to tackling the invasive issues of the species. (17)

Availability
Wild-crafted.

September 2023

                                                 PHOTOS / ILLUSTRATIONS
IMAGE SOURCE: Photo: Salvinia molesta - the acquatic fern / Eric Guinther / CC BY 2.5 / click on image or link to go to source page / Wikipedia
OTHER IMAGE SOURCE: Photo: Salvinia molesta / © CAL•IPC / Noncommercial use / click on image or link to go to source page / CAL•IPC
OTHER IMAGE SOURCE: Photo: Salvinia molesta - leaf surface / © Kevin Faccenda / CC by 4.0 / click on image or link to go to source page / Extension Gardener - North Carolina Plant Toolbox

Additional Sources and Suggested Readings
(1)
Salvinia molesta / KEW: Plants of the World Online
(2)
xxxxxx
(3)
Salvinia molesta / Global Invasive Species Database
(4)

Antioxidant activity, total phenol, flavonoid, alkaloid, tannin, and saponin contents of leaf extracts of Salvinia molesta D. S. Mitchell (1972)  / Asian Journal of Pharmaceutical and Clinical Research, 2016; 9(1): pp 185-188 /  HERO ID: 8391379
(5)
Phytochemical,Antibacterial and GC MS analysis of a floating fern Salvinia molesta D.S.Mitchell (1972) 
/ T G Nithya, Jayanthi J, Raghunathan M G / International Journal of PharmTech Research, 2015; 8(9): pp 85-90 / ISSN: 0974-4304
(6)
A Preliminary Phytochemical Study of Salvinia molesta, North Paravur, Ernakulam, Kerala, India / Gaya KS, Ramesh Babu MG, Lizzy Mathew / Journal of Global Biosciences, 2016; 5(1): pp 3437-3441 / ISSN: 2320-1355
(7)
Phenolic and other constituents of fresh water fern Salvinia molesta / Muhammad Iqbal Choudhary, Nadra Naheed, Ahmed Abbaskhan, Syed Ghulam Musharraf / Phytochemistry, 2008; 69(4): pp 1018-1023 /
DOI: 10.1016/j.phytochem.2007.10.028
(8)
New isolate from Salvinia molesta with antioxidant and urease inhibitory activity 
/ Nadra Naheed, Saima Maher, Farooq Saleem, Ajmal Khan, Abdul Wadood et al /  Drug Dev Res., 2021; 82(8): pp 1169-1181 /  DOI: 10.1002/ddr.21831
(9)
Column chromatography and HPLC analysis of phenolic compounds in the fractions of Salvinia molesta mitchell / T G Gini, G Jeya Jothi /  Egyptian Journal of Basic and Applied Sciences, 2018; 5(3): pp 197-203 / DOI: 10.1016/j.ejbas.2018.05.010
(10)
Cytotoxic compounds from invasive giant salvinia (Salvinia molesta) against human tumor cells / Shiyou Li, Ping Wang, Guangrui Deng, Wei Yuan, Zushang Su / Bioorganic & Medicinal Chemistry Letters, 2013; 23(24): pp 6682-6687 / DOI: 10.1016/j.bmcl.2013.10.040
(11)
Immunomodulatory activity of Salvinia molesta D.S. Mitchell in fresh water crab Oziotelphusa senex senex bacterially challenged with Pseudomonas aeruginosa / T G Nithya, D Sumalatha, M G Ragunathan, J Jayanthi / Journal of King Saud University - Science, 2019; 31: pp 1471-1477 /
DOI: 10.1016/j.ksus.2018.07.008
(12)
Photo-catalyzed and phyto-mediated rapid green synthesis of silver nanoparticles using herbal extract of Salvinia molesta and its antimicrobial efficacy /  Devendra Kumar Verma, Syed Hadi Hasan, Rathindra Mohan Banik / Journal of Photochemistry and Photobiology B: Biology, 2016; Volume 155: pp 51-59 /
DOI: 10.1016/j.jphotobiol.2015.12.008
(13)
Recent studies on applications of aquatic weed plants in phytoremediation of wastewater: A review article / Hauwa M Mustafa, Gasim Hayder /  Ain Shams Engineering Journal, 2021; 12(1): pp 355-365 / DOI
DOI: 10.1016/j.asej.2020/05.009
(14)
Salvinia molesta phytoremediation capacity as a nature-based solution to prevent harmful effects and accumulation of ciprofloxacin in Neotropical catfish /  Rafael Shinji Akiyama Kitamura, Maiara Vicentini, Marcelo Pedrosa Gomes et al /  Environmental Science and Pollution Research, 2023; 30: pp 41848-41863 / DOI: 10.1007/s11356-023-25226-y
(15)
Exploring the underwater air-retaining ability and thermal insulating effect of terry fabrics inspired by Salvinia molesta / Yawen Zheng, Xiang Zhou, Tianmin Tu et al / Textile Research Journal, 2018; 89(14) / DOI: 10.1177/0040517518803795
(16)
Phytoremediation potential of Salvinia molesta for arsenite contaminated water: role of antioxidant enzymes / Adinan Alves da Silva, Alan Carlos Costa et al / Theoretical and Experimental Plant Physiology, 2018; 30: 275-286 / DOI: 10.1007/s40626-018-0121-6
(17)
From Invasive to Creative: Transforming Salvinia molesta in Taman Botani Sri Medan into Cosmeceutical Solid Soap /  Nurul Syamimi Muzaini, Furzani Pa'ee /  Proceedings of the 7th International Conference on Biological Science (ECBS 2021) / DOI: 10.2991/absr.k.220406.003

DOI: It is not uncommon for links on studies/sources to change. Copying and pasting the information on the search window or using the DOI (if available) will often redirect to the new link page. (Citing and Using a (DOI) Digital Object Identifier)

                                                            List of Understudied Philippine Medicinal Plants

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