 Botany
Pako is a terrestrial fern with a creeping
rhizome and stout black roots on the under-surface. Compactly
situated leaves are borne spirally, reaching a height of 1 meter
or more. Rhizome bears narrow, tapering toothed scales, about
1 centimeter long. Leaves are 2- or 3-pinnate; 50 to 80 centimeters long; the
pinnules are lanceolate, 5 centimeters long, and rather coarsely toothed. Sori are superficial
and elongate, arranged in pairs on the side of the veins or veinlets.
Distribution
- Widely distributed in the Philippines,
common on gravel bars and banks of streams.
- Found from India to Polynesia.
 Constituents
- Rich in micronutrients, beta-carotene, folic acid, minerals (Ca, Fe, and P). Anti-nutritional factors like phytic acids, trypsin, and tannins are present, but in quite safe quantities. (13)
- Study of fresh plant samples yielded 91.82% moisture, 1.42% ash, 0.28% crude fat, 0.87% crude protein, and 0.72% crude fiber. Oven dried samples yielded 17.39% ash,3.40% crude fat, 0.87% crude protein, and 9.06% crude fiber. (19)
- Qualitative analysis of ethanol and aqueous leaf extracts yielded alkaloids, reducing sugars, anthraquinones, anthranol glycosides, cyanidins, phenols, saponins, and proteins. Cardiac glycosides, leucoanthocyanins, phytosterols, diterpenes, and triterpenes were detected only in the ethanol extract. Total phenolic contents were 125.60 ± 13.44 and 11.65 ± 0.87 mg gallic acid equivalents and total flavonoid contents were 110.81 ± 11.16 and 16.21 ± 0.72 mg quercetin equivalents per 100 g air-dried sample for ethanol and aqueous extracts, respectively. (19)
- GC-MS analysis of rhizomes yielded 18 compounds:
Tetradecanoic acid, N-hexadecanoic acid, Octadecane, Pentadecanoic acid, Hexahydrofarnesyl acetone, Pentadecanoic acid, Docosane, N hexadecanoic acid, octadecanoic acid, Octadecane, 5-methyl, Hexadecanoic acid, 2hydroxy 1 ethyl ester, Hexacotaine, Tetracosane, 1-Tricosane, 10-Methyl-Octadec-1-ene, Tetra pentacotane. (see study below) (21)
- Phytochemical evaluation of leaf extracts yielded flavonoids, steroids, carbohydrates, glycosides, alkaloids, proteins and phenolic compounds. (see study below) (22)
- Phytochemical screening of an ethanol extract showed the presence of saponin glycosides, flavonoids, proteins, and fixed oils. (see study below) (28)
- Nutrient content of hot air oven dried green leafy vegetable (g/100g) yielded edible portion of 54 g, ash 14.42g, moisture 71.74 g, lipid 0.34 g, crude protein 18.32 g, carbohydrate 5.45 g, crude fiber 4.45 g, calorific value 195 kcal. Miscellaneous values were ascorbic acid 23.59 mg/100g, ß-carotenoid 4.65 mg/100g, antioxidant activity by DPPH 94.94 % inhibition, and phenolic content of 2.39 mg/g. (31)
- Mineral content (mg/100g) of hot air oven dried green leafy vegetable yielded iron 38.20, zinc 4.30, copper 1.70, manganese 21.11, sodium 29.00, potassium 74.46, calcium 52.66, and magnesium 15.30.
Antinutritional content (mg/100g) yielded oxalic acid 1.72, tannin 10.19, and phytic acid 103.16. (31)
- Study for trace elements in roots (R) and leaves (L) in riverside (r) and farmland (f) (µg/g dry weight) yielded aluminum 288.9 Rr / 158.4 Rf and 6.3 Lr / 3.9 Lf; iron 162.5 Rr / 438.5 Rf and 3.3 Lr / 3.1 Lf; manganese 14.1 Rr / 8.2 Rf and 1.5 Lr / 2.0 Lf. (35)
Properties
- Studies have shown antimicrobial, antioxidant, anti-inflammatory, anticoagulative, antidiabetic, immunosuppressive properties.
Parts
utilized
Rhizomes and young leaves.
Uses
Nutritional
· Young fronds are eaten
as a leafy vegetable, raw or cooked; or as an ingredient in salads
or stews.
· A good source of calcium, phosphorus, iron and vitamin
B.
Folkloric
· Decoction of the rhizomes
and young leaves, simple or sugared, used for hemoptysis and coughs.
· In India, boiled young fronds taken with boiled rice as vegetables for laxative effect.
· In Western Ghats, India, juice from leaves taken orally twice daily for colds and cough. (29)
· Leaves used for headache, pain, fever, wounds, dysentery, diarrhea, and various skin infections.
· Aerial parts used to treat hemoptysis and coughs; rhizomes used for diarrhea, dysentery and coughs; leaves used to treat fever, dermatitis, measles, coughs, and as postpartum tonic; rots used for fever, dermatitis and as hair tonic. (24)
Others
· Gardening: Wiry roots sold as "osmunda roots" for growing
orchids, esp. Cattleyas.
· Livestock: Mature fronds used as fodder. (•) In Assam, India, used for treating hump sores in domestic animals.
 Studies
• Antimicrobial:
In a study of ethanol extracts of 19 Malaysian traditional vegetables, six extracts, including Diplazium esculentum, showed antimicrobial activity. (2)
• Antioxidant: In a study of the antioxidant activity of shoots of three selected local vegetables, results showed significant differences in the boiled and fresh samples of the vegetables. D. esculentum rated 2nd (fresh) and 5th (boiled). (3)
• Antifungal: In a study of the methanolic extracts of leaves, stems and roots of four ferns for activity against A. niger, R stolonifer and Candida albicans, results showed a broad spectrum of antifungal activity for D. esculentum leaves. (4) In a study of eight species of medicinal plants, a choloroform extract of D. esculentum demonstrated fungistatic activity against all fungi with MIC values ranging from 0.02 to 2.50 mg/ml. (24)
• Antibacterial: Study of aqueous and alcoholic extracts of DE showed activity against human and plant pathogenic bacteria like E. coli, Salmonella arizonae, S. typhi, Staph aureus. Tetracycline was the reference standard antibiotic. All extracts mixed in equal proportion with the antibiotic were more effective against the bacteria than the antibiotic alone. (5)
• Fern Toxin / Ptaquiloside (Pta): Pta, a nor-sesquiterpenoid glycoside is considered clastogenic, mutagenic, and carcinogenic. A few samples of Diplazium esculentum showed moderate levels, while most samples had no detectable Pta presence. (6)
• Anti-Anaphylactic / Mast Cell Stabilizing Activity: Study evaluated the anti-anaphylactic and mast cell stabilizing activity of Diplazium esculentum in sensitized rats. Aqueous and ethanol extract showed protective activity in in vitro passive anaphylaxis. Both also showed marked protection against induced mast cell degranulation. Results clearly substantiated the beneficial effects of the vegetable fern. (8)
• Anthelmintic / Rhizomes: Ethanolic, aqueous, and petroleum ether extracts of rhizome were studied for anthelmintic activity against Pheretima posthuma. All extracts showed significant anthelmintic activity, with the ethanolic extract showing the more potent activity. (9)
• Anti-Thiamine Factors: Twenty-six kinds of raw vegetables were studied for anti-thiamine factors. Two of the twenty-six tested vegetables, Pak Good (Athyrium esculentum) and Pak Van (Marsilea crenata) showed thiaminase activity. Pak Good also showed a thermostable factor, together with eighteen other vegetables. (10)
• Pathological Effects in Lab Rats and Guinea Pigs: Study showed linguda (Diplazium esculentum) caused mild pathologic effects in rats while feeding of frozen linguda induced mortality and moderate type of clinico-pathologic effects in guinea pigs. (11)
• Anti-Inflammatory Effects / Leaves: Study evaluated the anti-inflammatory effect of different extracts of leaves of Diplazium esculentum in rats using carrageenan hind paw edema assay. Results showed all extracts exhibited anti-inflammatory activity, more in the chloroform extract group than other treated groups. Ibuprofen was used as standard drug. (14) Study evaluated various extracts of leaves of Diplazium esculentum for anti-inflammatory activity using carrageenan induced hind paw edema. All extracts showed anti-inflammatory activity, with the chloroform extract showing higher percentage of inhibition. Ibuprofen was used as standard. (33)
• Antioxidant / Antimicrobial / Cytotoxic: Study evaluated the antioxidant, antimicrobial, and cytotoxic properties of the leaf of D. esculentum in different in vitro experimental models. Chloroform and methanol extracts showed strong antioxidant activity in cupric ion reducing capacity assay. Extracts showed strong antimicrobial activity, with the chloroform extract showing zones of inhibition of S. lutea > S. typhimurium > B. subtilis > K. pneumonia > S. boydii > E. coli > S. aureus > V. cholera. Cytotoxic activity was evaluated by brine shrimp lethality bioassay. (15)
• Immunosuppressive and Hemolytic Effects: Study evaluated the immunosuppressive and hemolytic activities of boiled D. esculentum in Swiss albino mice. BDE fed mice showed a significant decrease in body weight and relative spleen weight. There was significant dose-dependent decrease in the number of cultured splenocytes and dose dependent increases in percentage inhibition of splenocyte proliferation as well as percentage hemolysis by in vitro assays. Results suggest consumption of D. esculentum is alarming and may act as an immunosuppressive agent. (16)
• Analgesic / Flavonoid and Sterols / Leaves: Study evaluated the analgesic activity of various leaf extracts of D. esculentum using acetic acid induced writhing in a mice model. An aqueous extract showed potent analgesic activity with marked beneficial effects against central and peripheral inflammatory pain models. The protective action may be attributed to the presence of flavanoid and sterols. (17) Study evaluated the analgesic activity of semi-purified flavonoids of D. esculentum ethanolic extract using acetic acid induced writhing method in Swiss albino mice. Results showed analgesic activity increasing as the dose increases. (28)
• Silver Nanoparticles / Photocatalytic and Anticoagulative: Study describes the biosynthesis of silver nanoparticles with the leaf powder used as both reductant and stabilizer. Study also studied the NP as catalyst in degradation of methylene blue and rhodamine dyes and investigated the ability of AgNPs to inhibit coagulation of human blood plasma. (18)
• Glucosidase Inhibitory Activity / Cytotoxicity / Antidiabetic: Study evaluated the glucosidase inhibitory activity of five selected edible and medicinal ferns, viz. Blechnum orientale, Davalia denticulata, Diplazium esculentum, Nephrolepis biserrata, and Pteris vittata. Diplazium esculentum a-glucosidase inhibitory activity was considerably stronger than myricetin and the four other medicinal ferns. D. esculentum also showed dose-dependent cytotoxicity against K562 cells. (20)
• Biologic Constituents: GC-MS analysis of rhizomes yielded 18 compounds. Dominant compounds were n-hexadecanoic acid, tetradecanoic acid, di-n-octyl phthalate, tetra pentacotaine, octadecanoic acid. N-hexadecanoic acid (Palmitic acid) has known antioxidant, hypocholesterolemic, pesticide, lubricant, antiandrogenic properties, among others. Di-n-octyl phthalate has antifungal properties. Octadecanoic acid has potential antibacterial and antifungal activity. (see constituents above) (21)
• Acute Oral Toxicity Study / Leaves: A two-week acute oral toxicity study of leaves of D. esculentum showed the highest dose at 5000 mg/kg body weight. The plant was non-toxic to the experimental model. (see constituents above) (22)
• Hepatoprotective / Anti-Inflammatory: Study evaluated the anti-inflammatory and hepatoprotective activities of Diplazium esculentum. Results showed hepatoprotective activity with inhibitory effects on CCl4-induced hepatotoxicity. A methanol extract showed the highest inhibition of cyclooxygenase-2 (COX-2) and lipoxygenase (5-LOX) at concentration of 1000 µg. (23)
• Flavonoid Content and Antioxidant Activity: In a study of various ferns, Diplazium esculentum yielded a flavonoid content of 19.974 mg QE / g dried and antioxidant activity with 24.590 percent inhibition by DPPH assay. (25)
• Effect on Male Reproductive Functions / Antifertiliity: Study evaluated the effects of boiled D. esculentum on male reproductive functions of Swiss albino mice. Significant dose- and time-dependent decreases were observed in body weight, absolute- and relative-testis weight, organ weights, biochemical parameters, % of live spermatozoa and % of fertility and fecundity in BDE fed mice. Results suggest intake of D. esculentum, even after cooking, may induce infertility by altering male reproductive function, suggesting potential as antifertility agent. (26)
• Anticholinesterase and NADH Oxidase Inhibitory Activities / Antioxidant: Study investigated the acetycholinesterase and NADH oxidase inhibitory activities and free radical scavenging and total antioxidant activities in the linoleic acid system. Results showed dose-dependent inhibition of acetyl-
cholinesterase and NADH oxidase, with IC50s of 272.97 ± 19.38 and 265.81 ± 21.20 µg/mL, respectively. The extract showed potent radical scavenging activity with IC50 402.88 ± 12.70 µg/mL and total antioxidant activities of 27.41% and 33.22% by FTC and TBA methods, respectively. Results suggest a potential source of natural antioxidants. (27)
• Central Nervous System Effect / Antioxidant: Study of various extracts of D. esculentum showed significant (p<0.0001) and dose-dependent CNS stimulant effect at all doses tested. The water extract (7.6 mM/dry weight) showed highest antioxidant activity using FRAP assay. (30)
• Study on Pathological Effects: Study evaluated the clinical, hematological, biochemical and immunopathological effects of frozen (FL) and shade-dried linguda (SDL) @ 30% feeding in concentration ration or as green fodder for 30 days to rats and guinea pigs. Study concluded that linguda caused mild pathologic effects in rats while feeding of frozen linguda induced mortality and moderate type of clinico-pathological effects in guinea pigs. (34)
Availability
Wild-crafted.
Common market produce.
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