Piper, thepepper plants orpepper vines, is an economically and ecologically importantgenus in thefamilyPiperaceae.
It contains about 1,000–2,000species of shrubs, herbs, andlianas, many of which are dominant species in their native habitat. The diversification of this taxon is of interest to understanding the evolution of plants.
Pepper plants belong to themagnoliids, which areangiosperms but neithermonocots noreudicots. Theirfamily,Piperaceae, is most closely related to the lizardtail family (Saururaceae), which in fact generally look like smaller, more delicate andamphibious pepper plants. Both families have characteristic tail-shapedinflorescences covered in tiny flowers. A somewhat less close relative is the pipevine family (Aristolochiaceae). A well-known and very close relative – being also part of the Piperaceae – are the radiator plants of the genusPeperomia.
The earliest fossil ofPiper is of †Piper margaritae from theLate Cretaceous (Maastrichtian) ofColombia.P. margaritae appears to be nested within the cladeSchilleria, indicating extensive Cretaceous diversification ofPiper into the multiple extant clades, coinciding with the final breakup ofGondwana. This contrasts with previous theories assuming a younger radiation of the genus. An earlier potential record is of †Piper arcuatile from theCenomanian toSantonianKaltag Formation ofYukon, although this affinity toPiper is not entirely reliable.[1][2][3]
Piper species have apantropical distribution, and are most commonly found in the understory of lowlandtropical forests, but can also occur in clearings and in higher elevation life zones such ascloud forests; one species – the Japanese Pepper (P. kadsura) from southernJapan and southernmostKorea – is subtropical and can tolerate light winterfrost. Peppers are often dominant species where they are found.
MostPiper species are eitherherbaceous orvines; some grow asshrubs or almost as smalltrees. A few species, commonly called "ant pipers" (e.g.Piper cenocladum), live in amutualism withants. The fruit of thePiper plant, called a peppercorn when it is round and pea-sized, as is usual, is distributed in the wild mainly bybirds, but small fruit-eatingmammals – e.g.bats of the genusCarollia – are also important. Despite the high content of chemicals that are noxious toherbivores, some haveevolved the ability to withstand the chemical defences of pepper plants, for example thesematurinemothHomidiana subpicta or someflea beetles of the genusLanka. The latter can be significantpests to pepper growers.
Many pepper plants make goodornamentals for gardens insubtropical or warmer regions. Pepper vines can be used much asivy intemperate climates, while other species, like lacquered pepper (P. magnificum) grow as sizeable, compact and attractive shrubs with tough and shiny leaves. Smallerspecies, like Celebes pepper (P. ornatum) with its finely patterned leaves, are also suitable as indoorpot plants.
Unsustainablelogging of tropicalprimary forests is threatening a number of peppers. The extent of the effect of such wholesalehabitat destruction on the genus is unknown, but in the forests ofEcuador – the only larger region for which comprehensive data exists[4] – more than a dozen species are known to be on the brink ofextinction. On the other hand, otherPiper species (e.g. spiked pepper,P. aduncum) have been widely distributed as a result of human activity and are a majorinvasive species in certain areas.
The most significant human use ofPiper is not for its looks however, but ultimately for the wide range of powerfulsecondary compounds found particularly in the fruits.
Culinary use of pepper plants is attested perhaps as early as 9,000 years ago. Peppercorn remains were found among the food refuse left byHoabinhian artisans atSpirit Cave,Thailand. It is likely that these plants were collected from the wild rather than deliberately grown.[5][6]
Black pepper (Piper nigrum) corns, from left to right: Green (pickled unripe fruits) White (dried ripe seeds) Black (dried unripe fruits)
Use of peppercorns as pungent spice is significant on an international scale. Byclassical antiquity, there was a vigoroustrade of spices including black pepper (P. nigrum) fromSouth Asia toEurope. TheApicius, a recipe collection complied about 400 AD, mentions "pepper" as a spice for most main dishes.[7] In the lateRoman Empire, black pepper was expensive, but was available readily enough to be used more frequently thansalt[a] orsugar.
As Europe moved into theEarly Middle Ages, trade routes deteriorated and the use of pepper declined somewhat, but peppercorns, storing easily and having a high mass per volume, never ceased to be a profitable trade item. In theMiddle Ages, international traders were nicknamedPfeffersäcke ("pepper-sacks") inGerman towns of theHanseatic League and elsewhere. Later, wars were fought by European powers, between themselves and in complex alliances and enmities withIndian Ocean states, in part about control of the supply of spices, perhaps the mostarchetypal being black pepper fruit. Today, peppercorns of the three preparations (green, white and black) are one of the most widely used spices of plant origin worldwide.
Due to the wide distribution ofPiper, the fruit of other species are also important spices, many of them internationally.Long pepper (P. longum), is possibly the second-most popularPiper spice internationally; it has a ratherchili-like "heat" and the wholeinflorescence is used as the fruits are tiny.Cubeb (P. cubeba), also known as tailed pepper, played a major role in the spice trade. ReputedlyPhilip IV of Spain suppressed trade in cubeb peppercorns at the end of the 1630s to capitalize on his share of the black pepper trade.[8] It remains a significant spice around theIndian Ocean region today, however. West African pepper (P. guineense), is commonly used inWest African cuisine, and is sometimes used in theEast Africanberbere spice mix. This species, despite being traded more extensively in earlier times, is less common outside Africa today.
Not only the seeds ofPiper are used in cooking. West African Pepper leaves, known locally asuziza, are used as a flavoring vegetable inNigerian stews. InMexican-influenced cooking,hoja santa or Mexican pepperleaf (P. auritum) has a variety of uses. InSoutheast Asia, leaves of two species ofPiper have major importance in cooking:lolot (P. lolot) is used to wrap meat for grilling in theIndochina region, while wild betel (P. sarmentosum) is used raw or cooked as a vegetable inMalay andThai cuisine;[9][10] The stems and roots ofPiper chaba are used as a spice inBangladeshi cuisine.
Cubeb (P. cubeba) has been used infolk medicine andherbalism as well as, particularly in the early 20th century, as acigarette flavoring.P. darienense is used medically by theKuna people of thePanama-Colombia border region, and elsewhere it is used to intoxicate fish which then can be easily caught.Spiked pepper, often calledmatico appears to have strongdisinfectant andantibiotic properties. Black pepper (P. nigrum)essential oil is sometimes used in herbalism, and long pepper (P. longum) is similarly employed inAyurveda, where it was an ingredient ofTriphala Guggulu and (together with black pepper) ofTrikatupills, used forrasayana (rejuvenating anddetoxifying) purposes.
OnePiper species has gained large-scale use as astimulant.Betel (P. betle) leaves are used to wrapbetel palm nut slices; its sap helps release the stimulating effect of these "cookies" which are widely known aspan inIndia.
Conversely, anotherPiper species,kava (P. methysticum), is used for itsdepressant andeuphoriant effects. In thePacific region, where it has been widely spread as acanoe plant, kava is used to produce a calming and socializing drink somewhat similar to alcohol andbenzodiazepines but without many of the negative side effects and less of anaddiction risk. It has also become popular elsewhere in recent decades, and is used as a medical plant. However, pills that contain parts of the whole plant have occasionally shown a stronghepatotoxic effect, which has led to the banning of kava in many countries. On the other hand, the traditional preparation of the root as a calming drink appears to pose little, if any, such hazard.[11][12][needs update]
Piper is amodel genus for research inecology and evolutionary biology. The diversity and ecological importance of the genus makes it a strong candidate for ecological and evolutionary studies. Most research has focused on the economically important speciesP. nigrum (black pepper),P. methysticum (kava), andP. betle (betel). A recent study based on DNA sequence analysis suggest thatP. nigrum originated in theWestern Ghats hot spot in India.[14]
The obligate and facultative[further explanation needed]antmutualists found in somePiper species have a strong influence on their biology, making them ideal systems for research on the evolution ofsymbioses and the effect of mutualisms on biotic communities.[citation needed]
Importantsecondary metabolites found in pepper plants arepiperine andchavicine, which were first isolated from Black Pepper, and reported to have antibiotic activities. Preliminary research reports has shown that piperine has an antibacterial activity against various bacteria such asS. aureus,[15][16]Streptococcus mutans,[17] and gastric cancer pathogenHelicobacter pylori[18] and decreasedH. pylori toxin entry to gastric epithelial cells.[19] Thepiperidinefunctional group is named after the former, andpiperazine (which is not found inP. nigrum in noticeable quantities) was in turn named after piperidine.
The largest number ofPiper species are found in the Americas (about 700 species), with about 300 species from Southern Asia. There are smaller groups of species from the South Pacific (about 40 species) and Africa (about 15 species). The American, Asian, and South Pacific groups each appear to bemonophyletic; the affinity of the African species is unclear.[22]
Some species are sometimessegregated into the generaPothomorphe,Macropiper,Ottonia,Arctottonia,Sarcorhachis,Trianaeopiper, andZippelia, but other sources keep them inPiper.[22]
