Botany
Kaya-kayapuan is an aquatic, herbaceous fern. Rootstock are slender, creeping, branched, the stipes of the sterile fronds 2 to 12 centimeters high, slender. Leaves are arranged in two rows on long, the young leaves sightly downy, on trailing, wiry stems. Leaflets are 4, light to dark green, obovate-cuneate, glabrous, 10 to 15 centimeters long or smaller in terrestrial forms, rounded and slightly crenate or subentire at the apex , the lateral margin entire, straight, cuneately narrowed to the sessile base. Sporocarps (spore bearing organ found near the rootstock) are covered with brown hairs when young, becoming glabrous and nearly so, oblong, about 3 millimeters long, rounded, slightly compressed, somewhat clustered or solitary, their pedicels 5 millimeters long or less, the upper basal tooth prominent.

Distribution
- Widely distributed in the Philippines; in muddy places, ditches, shallow pools, and rice fields.
- Found in Indonesia, Malaysia, India, and Sri Lanka.

Constituents
- Study for bioactives yielded alkaloids, saponins, phenolics and flavonoids. Protein content was as high as 4.4 mg/g. (7)
- Preliminary screening of dried M. crenata leaves and n-hexane extraction by GC-MS analysis yielded monoterpenoid, diterpenoid, fatty acid compounds and other unknown compounds. (12)

Properties
- Prepared drug sweet tasting with cooling nature.
- Diuretic, antiphlogistic and tranquilizer.

Parts used
· Entire plant.

Uses
Edibility / Culinary
· Leaves are used in Indonesian East Javanese cuisine, served with sweet potatoes and peanut sauce. (1)
· In Thailand, leaves are used in Isan cuisine, as Phak waen and eaten raw with Nam phrik chili dip. (1) In Thailand, young plants are consumed all year round. Young shoots or whole plant is eaten raw or parboiled (4)
Folkloric
· Used for neurasthenia, edema.
· Dosage: 15 to 25 gms of dried material or 30 to 60 gms fresh material in decoction.
· In the Rajshahi district of Bangladesh, used for hepatic disorders (jaundice, hepatitis). (13)

Studies
• No Effect on Endometrial Histopathology: Study of 96% ethanolic extract of semanggi leaf on female mice showed no significant histopathologic endometrial effect. (2)
• Antioxidant / Flavonoid Content: Study evaluated the flavonoid content and antioxidant activity from ferns such as D. esculentum, Marsilea crenata and D. querciforia. The flavonoid content of M. crenata was 11.202 mg/g dried. Antioxidant activity was determined using DPPH assay where M. crenata showed 27.644 inhibition on ethanol extraction. (3)
• Phenolic Content / Antioxidant Activity: Study evaluated five Thai vegetables for phytochemical contents, phenolic content and antioxidant activity. Marsilea crenata extract exhibited the highest phenolic content (3.6041 mg GAE/g dry weight) and showed the most potent antioxidant activity on DPPH assay (IC50=248.94µg/ml). The Marsilea extract also yielded alkaloids. (5)
• Early Detection of Lead Stress: Study showed that Pb concentration tends to inhibit the plant growth and suggests its potential use as an early detection remediation process. (6)
• Estrogen Effect / Potential for Hormone Replacement Therapy: Study evaluated the effects of water clover extract on estrogen and progesterone levels and its effect on uterine histology. Phytoestrogen content in water clover leaves was 538.0 pg/g, while dried clover increased to 1068.0 pg/g. Uterine histology showed some endometrial thickening. Results showed consumption of water clover extract has promise as replacement estrogen hormone therapy. However, further study is need to find the proper dose for human consumption. (8)
• Loliolide and Isololiolide / Potential Phytotoxic Substances: Study explored the phytotoxic properties and phytotoxic substances from Marsilea crenata. Aqueous methanol extracts showed inhibition various seedling growths (lettuce, alfalfa, cress etc). Inhibition increased with concentration. Two substances were isolated: loliolide and isololiolide. These compounds may be responsible for the phytotoxic effects of the extract and presents a potential of ruse in organic agriculture. (9)
• Renal Function Benefits in Urolithiasis / Leaves and Stalks: Study evaluated the effect of M. crenata leaves extract and stalk juice in preventing disturbances of kidney functions in ,male Wistar rats with urolithiasis. Results showed leaf extract and stalk juice can prevent kidney function disturbance in urolithiasis, as evidenced by decreases in BUN and increase in Cr clearance. (10)
• Anti-Helicobacter pylori Activity: Helicobacter pylori is recognized as a cause of gastritis, dyspepsia, peptic ulcers, and gastric carcinoma. Study evaluated the anti-Helicobacter pylori activity of 57 methanolic extracts of edible plants in Thailand. Marsilea crenata was one of eight plants found to have activity against H. pylori with MIC of 2.5 µg/ml compared to amoxicillin, positive control, with 7.8 µg/ml. (11)

Availability
Wildcrafted.