Wednesday, 27 September 2017
Food as Medicine: Fig (Ficus carica, Moraceae)
HerbalEGram: Volume 14, Issue 8, August 2017 Editor’s Note: Each month, HerbalEGram highlights a conventional food and briefly explores its history, traditional uses, nutritional profile, and modern medicinal research. We also feature a nutritious recipe for an easy-to-prepare dish with each article to encourage readers to experience the extensive benefits of these whole foods. With this series, we hope our readers will gain a new appreciation for the foods they see at the supermarket and frequently include in their diets. The basic materials for this series were compiled by dietetic interns from Texas State University in San Marcos and the University of Texas at Austin through the American Botanical Council’s (ABC’s) Dietetic Internship Program, led by ABC Education Coordinator Jenny Perez. We would like to acknowledge Perez, ABC Special Projects Director Gayle Engels, and ABC Chief Science Officer Stefan Gafner, PhD, for their contributions to this project. By Hannah Baumana and Jayme Bisbanob a HerbalGram Associate Editor b ABC Dietetics Intern (Texas State, 2016) Overview The fig (Ficus carica, Moraceae) is one of the oldest known cultivated fruit trees (its cultivation precedes the domestication of grains such as wheat [Triticum spp., Poaceae] and barley [Hordeum vulgare, Poaceae]) and has more than 700 known varieties.1 A multi-stemmed, deciduous sub-tropical shrub, the fig is one of more than 1,400 known species in the genus Ficus, which belongs to the mulberry family.2-4 What is commonly known as the fruit of the fig tree is technically a flower that has turned in on itself, a structure called a syconium.5 For the purposes of this article, this syconium will be referred to as the “fruit” of the plant. The fig also has a unique method of pollination, as it is dependent upon a family of wasps called agaonid wasps, also known as fig wasps. Agaonid wasps and the fig coevolved together over millennia and cannot thrive without each other.3 The wasps can lay eggs only within the fruit of the fig, and the fig can be pollinated only by agaonid wasps. The female wasp burrows into the immature fig, spreads pollen, and lays her eggs.6 When the eggs hatch, the males and females mate, collect pollen, and then exit the fig to pollinate other figs. Any wasp material that remains is digested by the maturing fig, and any fig that is not pollinated drops off the tree. The fig tree grows 15-30 feet (4.6-9.1 meters) tall with roughly textured palmate leaves that have three to five lobes each.5,7 The color of the ripe fruit is cultivar-dependent and can range from light green (Adriatic figs) to brown or dark purple (Mission figs), although genetic variation has waned as growers select for desirable traits of well-established fig cultivars.3,7 Fig trees were first found wild in Western Asia 6,500 years ago and were then brought by humans to the eastern Mediterranean area, where fig trees continue to flourish and grow wild.3,5,7 Phytochemicals and Constituents Figs are a good source of soluble and insoluble fiber. The soluble fiber content, which makes up about 28% of a fig’s total fiber content, is significant and has been shown to reduce low-density lipoprotein (LDL) cholesterol, as well as to help maintain blood sugar levels, because it slows the transit time of food in the gut.4,8,9 Four to five dried figs or two fresh figs provide roughly 12 grams of fiber, almost half of the 25-30 grams recommended daily intake for the average adult.2,4 Figs also provide calcium and iron: two micronutrients that are often deficient in specific populations or disease states.4,5,10 The protein in figs contains high levels of the amino acids aspartic acid and glutamine.2,9,11 The predominant bioactive compounds present in figs include phenolic compounds, phytosterols, anthocyanins, and organic acids that contribute to antioxidant activity. Figs also contain coumarins, which have demonstrated anti-inflammatory, anti-edema, and cytotoxic activities, and numerous volatile compounds that provide flavor and scent.3 Figs have a high amount of the flavonol quercetin, which has anti-inflammatory properties and can play an important role in preventing cardiovascular disease. Fig cultivars have varied antioxidant profiles correlated to their color: the darker varieties have the highest total polyphenol content while the light green varieties have the lowest total polyphenol content.10 The anthocyanin content of figs can help to maintain healthyblood lipid levels and play an important role in the prevention of obesity, diabetes, cardiovascular disease, and certain cancers.11 The latex of the fig fruit has both adverse effects and health benefits. The milky white, sticky substance present in unripe fruit contains alkaloids, tannins, a large amount of phytosterols, and fatty acids.2 However, there is evidence that the latex may cause irritation when used topically, and those who work with figs during the harvest often wear gloves to protect their skin.3 Fifty-nine volatile compounds have been identified in other parts of the plant including monoterpenes, sesquiterpenes, and norisoprenoids2,3. These compounds are present mainly in the fig leaves, with the exception of monoterpenes, which were found in the fruit peel and pulp. Of the anthocyanidins isolated from fig tree leaves, cyanidin and pelargonidin derivatives were the most predominant.2,3,10,12 Four triterpenoids were identified in the leaf: bauerenol, lupeol acetate, methyl maslinate, and oleanolic acid.2 Recent studies have confirmed that the highest levels of these bioactive compounds are found in the skin of the fig, and therefore support the evidence that most of the nutrients present in the plant are accessible through consumption of the whole fruit. The leaves and the roots of the fig tree contain plant sterols (specifically, modified triterpenes), which have been shown to lower cholesterol levels by blocking the absorption of exogenous cholesterol.2 Historical and Commercial Uses The flesh, pulp, leaves, roots, and latex from the fig tree have been used as part of the traditional medicine practices of India and China.3,4,10,13 Historically, figs have been used to treat numerous ailments, including common digestive issues such as poor appetite, colic, indigestion, constipation, dysentery, inflamed or ulcerated intestines, and intestinal parasites. They also provide antispasmodic, antibacterial, anti-inflammatory, and natural laxative effects.2,3,10,13 Additional uses of the fruit include the improvement of vision, alleviation of asthma, treatment of cardiovascular disorders and certain cancers (e.g., colon and lung), maintenance of blood sugar levels, and relief of sore throats and coughs. The latex of fig was used topically to treat boils and warts.2,3,10,13 In Pakistan, figs were not only traditionally used as food for humans, but also as feed for livestock, while the trees were used as fuel, roofing materials, tool handles, and even simply for the shade that mature plants can provide.13 Figs were also used as a source of sugar prior to the efficient cultivation of sugarcane (Saccharum officinarum, Poaceae).5 In some European countries, fig syrup enjoys widespread use as a mild laxative; the phenols, flavonoids, anthocyanins, and cellulose present in the fruit may contribute to its laxative effects.14 Modern Research Cardiovascular Health In a rat study, quercetin-3-O-rutinoside (rutin) in fig fruit was identified as being partly responsible for cholesterol-lowering activities.15 Rats that were fed a high-fat diet that was supplemented with fig fruit for eight weeks had greater reductions in total cholesterol levels, triglyceride levels, and LDL cholesterol levels, with increased high-density lipoprotein (HDL) levels compared to the control groups, one fed a normal diet without supplementation and one fed a high-fat diet without supplementation. These are all indicators that are monitored in the diagnosis of cardiovascular disease. Researchers speculated that rutin increased cholesterol excretion, while the polyphenol content of the plant inhibited the synthesis of cholesterol. Blood Sugar Regulation A study that investigated the antidiabetic potential of fig fruit consumption on blood sugar maintenance found that fig fruit had a significant inhibitory effect on α-amylase activity in diabetic rats. This enzyme hydrolyzes dietary carbohydrates (i.e., breaks the carbohydrates down into its component sugar molecules for easier elimination) in the pancreas.11 The study also found that the flavonoid content of figs had a hypoglycemic effect on rats, improved overall glucose metabolism, and reduced oxidative stress. Quercetin, when administered with glucose, aided in the efficient transport of glucose for proper digestion. Aqueous fig leaf extract also showed a hypoglycemic effect in diabetic rats, possibly due to its ability to increase plasma insulin levels.16 Cytotoxic Properties Fig leaf and fruit extracts, as well as fig latex, at relatively low concentrations, have exhibited in vitro efficacy against several cancer cell lines.16,17 Isolated compounds from fig wood resin have also been identified in experimental studies as potent cytotoxic agents that prevent proliferation of various cancer cell lines.18 Topical Applications Fig has been investigated for topical skincare applications. An open-label clinical trial found that a wart treatment made from fig latex was only marginally less effective than standard cryotherapy for the treatment of skin disturbances, with no adverse events reported in the fig treatment group.17 Additionally, a placebo-controlled clinical trial found that a base cream with fig fruit extract significantly increased skin hydration compared to the placebo cream, which did not contain the extract.19 Researchers concluded that the fig cream could help maintain healthy skin and lessen acne and the appearance of wrinkles. Nutrient Profile20 Macronutrient Profile: (Per 100 grams fresh figs [approx. two medium fruits]) 74 calories 0.8 g protein 19.2 g carbohydrate 0.3 g fat Secondary Metabolites: (Per 100 grams fresh figs [approx. two medium fruits]) Very good source of: Vitamin K: 4.7 mcg (11.8% DV) Dietary Fiber: 2.9 g (11.6% DV) Good source of: Potassium: 232 mg (6.6% DV) Vitamin B6: 0.1 mg (5% DV) Manganese: 0.1 mg (5% DV) Also provides: Magnesium: 17 mg (4.3% DV) Thiamin: 0.06 mg (4% DV) Calcium: 35 mg (3.5% DV) Vitamin C: 2 mg (3.3% DV) Riboflavin: 0.05 mg (2.9% DV) Vitamin A: 142 IU (2.8% DV) Iron: 0.4 mg (2.2% DV) Niacin: 0.4 mg (2% DV) Folate: 6 mcg (1.5% DV) Phosphorus: 14 mg (1.4% DV) DV = Daily Value as established by the US Food and Drug Administration, based on a 2,000-calorie diet. Recipe: Goat Cheese-Stuffed Figs with Pistachios and Balsamic Glaze Adapted from Janette Fuschi21 Ingredients: 1 cup balsamic vinegar 2 teaspoons sugar (optional) 12 ripe, fresh figs, washed, stems removed 4 ounces soft goat cheese 1/4 cup pistachios, unshelled and roasted Directions: Add the balsamic vinegar and sugar to a small saucepan. Heat over medium heat until simmering and stir until sugar dissolves. Maintain a low simmer for about 10-15 minutes until the vinegar thickens enough to coat the back of a spoon. Remove from heat and cool to room temperature. Cut a deep ‘X’ on the top of each fig without cutting through the bottom of the fruit. Stuff each fig with a small piece of goat cheese. Place the figs upright on a baking sheet. Position an oven rack six inches from the broiler element and heat the broiler. Broil figs for about five minutes, until cheese bubbles. Remove from oven. Sprinkle figs with pistachios and drizzle with balsamic glaze. Serve warm. Photo credit: All images ©2017 Steven Foster References Condit IJ. Fig varieties: a monograph. Hilgardia. 1955;23(11):323-538. http://doi.org/10.3733/hilg.v23n11p323. Barolo MI, Ruiz Mostacero N, López SN. Ficus carica L. (Moraceae): An ancient source of food and health. Food Chem. 2014;164:119-127. doi:10.1016/j.foodchem.2014.04.112. Mawa S, Husain K, Jantan I. Ficus carica L. (Moraceae): Phytochemistry, traditional uses and biological activities. Evidence-Based Complementary and Alternative Medicine. 2013;2013: 974256. doi:10.1155/2013/974256. Slavin J. Figs: past, present, and future. Nutr Today. June 2006;4:180-184. Bateman H, Berton M, Doig F, Driver E, Mapps J, Quintrell S, eds. Edible: An Illustrated Guide to the World’s Food Plants. Washington DC: National Geographic Society; 2008. Jousselin E, Hossaert-McKey M, Herre EA, Kjellberg F. Why do fig wasps actively pollinate monoecious figs? Oecologica. 2003;134:381-387. van Wyk BE. Food Plants of the World: An Illustrated Guide. Portland, OR: Timber Press, Inc.; 2005. Peterson JM, Montgomery S, Haddad E, Kearney L, Tonstad S. Effect of consumption of dried California mission figs on lipid concentrations. Ann Nutr Metab. 2011;58(3):232-238. doi:10.1159/000330112. Solomon A, Golubowicz S, Yablowicz Z, et al. Antioxidant activities and anthocyanin content of fresh fruits of common fig (Ficus carica L.). J Agric Food Chem. 2006;54:7717-7723. Harzallah A, Bhouri AM, Amri Z, Soltana H, Hammami M. Phytochemical content and antioxidant activity of different fruit parts juices of three figs (Ficus carica L.) varieties grown in Tunisia. Ind Crops Prod. 2016;83:255-267. Wojdyło A, Nowicka P, Carbonell-Barrachina ÁA, Hernández F. Phenolic compounds, antioxidant and antidiabetic activity of different cultivars of Ficus carica L. fruits. J Funct Foods. 2016;25:421-432. doi:10.1016/j.jff.2016.06.015. Wang H, Nair MG, Strasburg GM, et al. Antioxidant and antiinflammatory activities of anthocyanins and their aglycon, cyanidin, from tart cherries. J Nat Prod. 1999;62:294-296. Abbasi AM, Shah MH, Li T, Fu X, Guo X, Liu RH. Ethnomedicinal values, phenolic contents and antioxidant properties of wild culinary vegetables. J Ethnopharmacol. 2015;162:333-345. doi:10.1016/j.jep.2014.12.051. Baek HI, Ha KC, Kim HM, et al. Randomized, double-blind, placebo-controlled trial of Ficus carica paste for the management of functional constipation. Asia Pac J Clin Nutr. 2016;25(3):487-496. Belguith-Hadriche O, Ammar S, Contreras MDM, et al. Antihyperlipidemic and antioxidant activities of edible Tunisian Ficus carica L. fruits in high fat diet-induced hyperlipidemic rats. Plant Foods Hum Nutr. 2016;71:183-189. doi:10.1007/s11130-016-0541-x. Badgujar S, Patel VV, Bandivdekar AH, Mahajan RT. Traditional uses, phytochemistry and pharmacology of Ficus carica: A review. Pharmaceutical Biology. 2014;52(11):1487-1503. Jing L, Zhang YM, Luo JG, Kong LY. Tirucallane-type triterpenoids from the fruit of Ficus carica and their cytotoxic activity. Chemical and Pharmaceutical Bulletin. 2015;63(3):237-243. Rubnov S, Kashman Y, Rabinowitz R, Schlesinger M, Mechoulam R. Suppressors of cancer cell proliferation from fig (Ficus carica) resin: isolation and structure elucidation. J Nat Prod. July 2001;64(7):993-996. Khan H, Akhtar N, Ali A. Effects of cream containing Ficus carica L. extract on skin parameters: in vivo evaluation. Indian J Pharm Sci. 2014;76(6):550-564. Basic Report: 09089, Figs, raw. United States Department of Agriculture Agricultural Research Service website. Available at: https://ndb.nal.usda.gov/ndb/foods/show/2201. Accessed July 19, 2017. Fuschi J. Warm figs with goat cheese, pistachios and balsamic glaze. Culinary Ginger website. August 21, 2015. Available at: http://culinaryginger.com/warm-figs-with-goat-cheese-pistachios-and-balsamic-glaze/. Accessed July 19, 2017.