Letsugas is an erect, usually simple, annual, smooth, very leafy herb reaching a height of 1 meter when in flower. Leaves are stalkless, obovate to oblong-obovate, 6 to 20 centimeters long, entire or lobed, toothed, thin, and numerous at the base. Heads are numerous, about 1 centimeter long, and borne in open panicles; the branches, often much reduced, bear bractlike leaves. Flowers are yellow. Involucral bracts are ovate, the inner ones linear. Achenes are brown, with a very slender beak about as long as the body.
- Common commercial and garden cultivation for food.
- Nowhere established.
- Leaves yield a bitter principle (lactucin),mannite, mallic acid, asparagin, and oxalic acid.
- The whole plant yields a volatile oil, vitamin A, and a trace of hyoscyamine.
- Latex contains d- and B-lectucerol, inosite, reducing sugar, and a bitter principle.
- Lacturacium or lettuce opium, mentioned in the old pharmacopoeias, is the milky juice of the plant.
- Phytochemical study of a methanol extract have yielded triterpenoids, saponins, and simple phenols.
- Yields antioxidants like quercetin, caffeic acid and vitamin C.
Cooling and refreshing.
Anodyne, purgative, diuretic diaphoretic, antispasmodic, mildly soporific and hypnotic.
The ancients considered it an aphrodisiac.
Fresh plant extract considered a milk sedative.
Seeds are aromatic and bitter.
Juice, leaves, seeds.
Culinary / Nutrition
- Excellent source of vitamins A and C; a good source of vitamin B, carotene, and vitamin E.
- Early leaves, eaten as salad, are easily digested, but yields a poor amount of nutritive matter.
- Flowering plant produces, in feeble degree, the effects of lacturacium.
- Juice used as substitute for opium.
- Extract from fresh plant is a mild sedative; also, useful in the treatment of coughs in phthisis, bronchitis, asthma, and pertusis.
- In ancient folk medicine, used as appetite stimulant and aid to sleep.
- Lettuce poultice used as soothing application to painful and irritable ulcers.
- Infusion of seeds given in fevers, especially typhoid.
- Seeds also given for excessive thirst and to provide a sensation of heat in the stomach.
- Decoction of seeds used as demulcent; also as sedative and for treatment of insomnia.
- Believed to relax the genitalia and diminish spermatic secretion.
- Seeds, boiled or made into confection, useful for chronic bronchitis.
- In Iran, seeds are use for relieving inflammation and osteodynia.
• Analgesic / Anti-Inflammatory: Study of crude methanol/petroleum ether extract of seeds showed time- and dose-dependent analgesic effect in formalin test and a dose-dependent anti-inflammatory activity in a carrageenan model of inflammation. (1)
• Antioxidant / Protection Against D-Galactose Induced Oxidative Stress: Study showed L. sativa protected neurons from accumulation of lipofuscin granules, proving itself an effective antioxidant. (Lipofuscin or age pigment is a yellowish-brown autofluorescent, protein and lipid containing pigment that accumulates in the lysosomes of a variety of post mitotic cells including neurons and cardiac myocytes during ageing.) Results showed L. sativa protects against D galactose-induced oxidative stress and reduces accumulation of lipofuscin granules. (2)
• Antioxidant: Study of methanolic extract of leaf showed significant antioxidant potential both in vitro and in vivo. (8)
• Anti-Inflammatory: Study isolated bioactive anti-inflammatory compounds: 3,14-Dihydroxy-
11,13-dihydrocostunolide and 8-Tigloyl-15-Deoxyl-actucin. Both showed substantial lipooxygenase inhibitory activity and significant in-vivo anti-inflammatory activity on a carrageenan-induced paw edema model. (3)
• Polyphenols / Greenhouse vs Open-air: Study of lettuce extracts showed higher flavonol contents in open-air samples than the greenhouse ones. (4)
• Antinociceptive / Opioid Pathway: Study showed a remarkable nociceptive effect. An opioid pathway is a possible mechanism. (6)
• Neuroprotective: Study evaluated the capability of L. sativa in protecting neurons against glucose/serum deprivation (GSD)-induced cell injury, an in vitro model of brain ischemia. Results showed an intermediate polarity fraction of L. sativa exhibited neuroprotection and presents a potential therapeutic strategy for common neurodegenerative disorders such as stroke. (9)
• Antioxidants / Fresh Vs Stored Lettuce: Study evaluated whether storage under modified-atmosphere packaging affected the antioxidant properties of fresh lettuce. Results showed no changes after ingestion of MAP-stored lettuce in all markers. MAP-stored lettuce did not modify plasma redox status in healthy subjects. (10)
• Case of Hypersensitivity to Lettuce: A report of clinical sensitization to lettuce was reported with mucocutaneous manifestations. CAP inhibition showed antigenic community between lettuce and mugwort. Four protein bands from the lettuce extracts exhibiting IgE-binding properties. (11)
• Anti-Spermatogenic Effects / Seeds: Study of hydroalcoholic and aqueous extracts of lettuce seed showed antipsermatogenic effects. The aqueous extract increase serum testosterone level in mice. Results suggest the lettuce seed has potential as a contraceptive agent. (12)
• Potentiating Effect on Pentobarbital-Induced Sleep: Study evaluated the sleep-prolonging effect of the plant in mice. Results showed lettuce potentiates pentobarbital hypnosis without major toxic effect. The responsible component is most likely non-polar agent)s) found in the n-butanol fraction. (13)
• Functional Food Properties: Study compared the functional food properties of selected commercial red and green lettuce. Both had strong antioxidant and anti-inflammatory properties. However, anthocyanin in red lettuce is an additional source of biological activity. The variation in phenolic contents and the lack of anthocyanins in green lettuce gives red lettuce a higher biological activity. (14)
• Safety and Effect of Seed Oil in Sleep Disorders: Study evaluated capsules of L. sativa seed oil in 60 patients suffering from insomnia. Improvements in the modified State-Trait Anxiety Inventory and Sleep rating scale scores were significantly greater in patients receiving seed oil. No side effects were attributable to the seed oil at the test dosage. (15)
• Protective Effects on CCl4-Induced Reproductive Toxicity: Study evaluated the protective effects of ethanolic extract of lettuce leaves against toxicity caused by carbon tetrachloride in reproductive system of rats. Results showed the extract augments the antioxidant defense mechanisms against CCl4-induced toxicity and suggests a potential therapeutic role in free radical mediated diseases. (16)
• Anti-Leukemic Effects: A water extract of lettuce Lactuca sativa inhibited the growth of HL-60 leukaemic cells and MCF-7 breast cancer cells, correlating with the activation of Chk2, the induction of tumour suppressor p21, and the severe downregulation of the proto-oncogene cyclin D1. The ethyl acetate extract induced HL-60 cell death, correlating with the acetylation of α-tubulin. (17)