## 1 Introduction  
Medicinal plants and their natural products have been a source of important drug discoveries for decades. Since 1981, of the 1394 small-molecule drugs approved by the FDA, 930 of them were derived, to some extent, from a natural product, with fourteen being direct isolates from medicinal plant sources [1]. Many of these medicinal plants continue to be a primary therapeutic source for a large portion of the population in developing countries in Asia, South America, and Africa. The family Rubiaceae contains many of these plants, of which the genus _Uncaria_ is prominent. This review focuses on _Uncaria tomentosa_ ([PERSON]) DC., commonly referred to as \"cat's claw\", a plant that is native to South and Central America. The name of this woody vine was derived from the long, cat claw-like thorns protruding from the stem at its leaf junctions. The phytochemical composition of the plant has been the subject of many studies that pre-date this review [2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12], with one of these studies purporting more than 50 phytochemicals originating from the plant [13].  
The interest in the specific phytochemical composition of _U. tomentosa_ comes from the plant's long history of medicinal use by indigenous people in the region. Peruvian tribes such as the Ashanika, Aguaurranta, Cashibo, and Shipibo have used the plant for centuries to treat a multitude of allments. Documentation from these cultures have indicated its use as a therapeutic for allergies, arthritis, asthma, diabetes, cancer, bacterial and viral infections, and other medicinal uses [14]. Scientific investigations into _U. tomentosa_ extracts and constituents have uncovered a range of biological activities, such as antioxidant, anti-inflammatory, antimicrobial, antiviral, and immunomodulating activity [11, 12, 13].  
Of the biological activities and potential medicinal purposes, this review focuses on its antibacterial properties. As a traditional medicine, _U. tomentosa_ has been documented in wound treatment, indicating potential as an antibacterial agent [14]. Recent investigations of the plant and its extracts have produced in vitro evidence of antibacterial activity [15; 16; 17; 18; 19]. Antimicrobial activity has been observed against both the latent and active forms of the bacterium _Borrelia burgdorferi_, the bacterium responsible for Lyme disease [20; 21]. Lyme disease is a tick-borne ailment brought on by the introduction of _Borrelia burgdorferi_ to a host through a tick bite. Recent Centers for Disease Control (CDC) investigations have indicated that as many as 300,000 Americans are affected by Lyme disease every year [22; 23]. Improved antibiotic therapies capable of not only treating the initial symptoms of _B. burgdorferi_ infections, but also preventing and treating persistent infections are needed. The in vitro anti-borrelia efficacy demonstrated by _U. tomentosa_ warrants an investigation into the possibility of identifying the constituent or a combination of constituents responsible for this effect.  
To date, several reviews have been published providing general information on the genus _Uncaria_, including _U. tomentosa_, which contain focused, but limited, information on constituents and/or bioactivity [11; 12; 13]. In addition, none of these reviews have focused specifically on _U. tomentosa_ constituents and their applications as antibacterial agents. The purpose of this review is to present a comprehensive collection of molecular structures from _U. tomentosa_, as well as consolidate research and literature regarding these components' potential as antibacterial candidates. The information provided in this review will hopefully highlight promising candidates for the possible development or isolation of antibacterial agents from the species _U. tomentosa_, and specifically those related to anti-borrelia efficacy.