Rubus Pharmacology: Antiquity to the Present

The genus Rubus L., indigenous to six continents, includes blackberries, raspberries, and their hybrids and is commonly referred to as brambles or briers. Rubus species were a food and medicinal source for native peoples soon after the Ice Age. This short article presents only a sample of the wealth of historical reports of medicinal uses for Rubus. Brambles were documented in the writings of the ancient Greeks: Aeschylus, Hippocrates, Krataeus, Dioscorides, and Galen; Romans: Cato, Ovid, and Pliny the Elder; Asian medicinal traditions; traditional Chinese medicine; and the Ayurvedic tradition of India. Folk traditions of native peoples throughout the world have also applied Rubus for multiple medicinal uses. Although in modern times Rubus is grown for its delicious and vitamin-rich fruit for fresh and processed product consumption, the ancients used the whole plant and its parts. Stems, branches, roots, leaves, and flowers were used in decoctions, infusions, plasters, oil or wine extractions, and condensates. Decoctions of branches were applied to stop diarrhea, dye hair, prevent vaginal discharge, and as an antivenom for snakebites. Leaves were chewed to strengthen gums and plastered to constrain shingles, head scurf, prolapsed eyes, and hemorrhoids. Flowers triturated with oil reduced eye inflammations and cooled skin rashes; infusions with water or wine aided stomach ailments. Greeks and Romans recorded female applications, whereas the Chinese described uses in male disorders. The fruits of R. chingii are combined in a yang tonic called fu pen zi, ‘‘overturned fruit bowl,’’ and prescribed for infertility, impotence, low backache, poor eyesight, and bedwetting or frequent urination. The Leechbook of Bald described the use of brambles against dysentery, combining ancient medicinal knowledge with pagan superstition and herb lore. Medicinal properties of Rubus continue in Renaissance and modern herbals, sanctioning leaf infusions as a gargle for sore mouth, throat cankers, and as a wash for wounds; the bark, containing tannin, was a tonic for diarrhea; and root extract, a cathartic and emetic. Recent research has measured high ellagic acid, anthocyanin, total phenolics, and total antioxidant content in Rubus fruits. Fruit extracts have been used as colorants and are now being tested as anticarcinogenic, antiviral, antiallergenic, and cosmetic moisturizing compounds. From ancient traditions through conventional folk medicines to the scientific confirmation of health-promoting compounds, Rubus is associated with health-inducing properties. Raspberry cultivation for fruit only became widespread in European countries by the 16th century (Jennings, 1988). Modern uses of Rubus, the blackberries and raspberries, include consumption as delicious fresh fruits and processed in jams, jellies, pastries, dairy products, and juices (Daubeny, 1996). Many breeders throughout the United States and Canada have developed plants with large succulent fruits having delicate sugar–acid ratios and complex flavors. These small or soft fruits have high antioxidant capacity, high anthocyanins, high vitamins, simple sugars, and high mineral content (Määtä-Riihinen et al., 2004; Moyer et al., 2002). Ancient references of Rubus in Western and Eastern traditions do not refer to berries as food; rather the stems, leaves, and other plant parts were prized for their medicinal properties (Beck, 2005). The object of this review is to summarize the uses of Rubus for health from antiquity to the present from a sampling of the wealth of historical data on this subject. Although the recent use of the fruits as fresh and processed foods represents a global multimillion dollar industry annually, interest in the medicinal qualities continues to expand. The genus Rubus Distribution. The genus Rubus, one of the most diverse in the plant kingdom, contains 740 species that have been divided into 12 or 15 subgenera, depending on the botanist (Daubeny, 1996; Jennings, 1988). These diverse species are native on six continents and have been found from the tops of mountains to coastal locations at sea level (Thompson, 1995). Although the raspberries and blackberries are common in cool temperate regions of the northern hemisphere, the majority of Rubus species are native to South Pacific Islands. Taxonomy. Blackberries are botanically classified in the genus Rubus subgenus Rubus (formerly Eubatus). European blackberries (Rubus fruticosus L. agg.) have a center of origin in the Caucasus, are well distributed throughout Europe, and have been introduced into Asia, Oceania, and North and South America. Subgenus Idaeobatus includes the European raspberries (Rubus idaeus L.) and the cloudberry (R. chamaemorus L.) native to southern European mountains (Tutin et al., 1980) and were named by Linnaeus for Mount Ida, Turkey; North American raspberries (R. strigosus Michx., R. spectabilis Pursh, R. parvifolius Nutt.) and black raspberries (eastern, R. occidentalis L. and western, R. leucodermis Douglas ex Torr. & A. Gray); and Asian species such as R. chingii Hu, R. coreanus Miq., R. crataegifolius Bunge, and R. parvifolius L. This species is mainly distributed in Zhejiang, Fujian, Hubei, and Guizhou provinces of China. Rubus hawaiiensis A. Gray from Hawaii as well as species in East and South Africa are among many used by native peoples. Rubus medicinal uses Plants synthesize a variety of medically active phytochemicals, but most are derivatives of alkaloids, phenolics, terpenoids, and glycosides. The phenolics are the biochemical motif most active in Rubus plants for ethnomedicinal applications. Rubus phenolics include the flavonoids, potent in vitro antioxidants, including compounds such as flavones, isoflavones, flavonones, catechins, and the red, blue, and purple pigments known as anthocyanins (Määtä-Riihinen et al., 2004; Moyer et al., 2002). Tannins, present in Rubus stems and leaves, have astringent properties. Many cultures, without knowledge of the particular chemical agents, have observed medicinal properties in Rubus and applied them in different ways (Gunther, 1934; Rohde, 1922). Prehistory. The use of herbs in the western hemisphere stretches back into antiquity, well into the Paleolithic or Old Stone Age era, 40,000 BCE. Rubus species were a food source and medicinal plant for native peoples soon after the Ice Age (Connolly, 1999). In the New World, archeologists found evidence of Rubus as a food source in Newberry Crater near Bend, OR. Radiocarbon dating puts the artifacts and food remnants at 8000 BCE (Connolly, 1999). Antiquity. Brambles were documented in the writings of Aeschylus (Hendrickson, 1981) and Hippocrates, between 500 to 370 BCE. Hippocrates recommended blackberry (batos) stems and leaves soaked in white wine as an astringent poultice on wounds and in difficulties Received for publication 14 July 2010. Accepted for publication 3 Sept. 2010. Financial support from USDA ARS CRIS 535821000-038-00D is acknowledged. The critical reviews by Dr. Jules Janick, Dr. Nahla Bassil, and Dr. Doug Holland are appreciated. This paper was part of the workshop ‘‘Horticulture and Health: Historical Resources’’ held 26 July 2009 at the ASHS Conference, St. Louis, MO, and sponsored by the History of Horticultural Science (HIST) Working Group. e-mail [email protected]. HORTSCIENCE VOL. 45(11) NOVEMBER 201