Changes

:Chromosome number: ''x''= 4, 5;''P. afra'': 2''n''= 12,''P. asiatica'': 2''n''= 12, 24, 36,''P. lanceolata'': 2''n''= 12 + 0-1B, 24,''P. major'': 2''n''= 12, 24,''P. ovata'': 2''n''= 8, 16

*''Plantago major'' L.

''Plantago'' consists of approximately 250 species and is cosmopolitan except the polar regions. It is essentially temperate in its natural distribution. Some species, particularly ''P. major'' and ''P. lanceolata'' , are extremely widespread, throughout temperate regions and also penetrating into tropical highland regions. ''P. major'' is the most widespread species in South-East Asia, and ''P. lanceolata'' is only very locally naturalized.

India is an important exporter of seed husks (mainly of ''P. ovata'' and to a lesser extent of ''P. afra'' ), especially to the United States, where annual imports were worth about US$ 3.5 million in the late 1980s. It has been estimated laxatives containing ''Plantago'' are daily used by about 4 million Americans.

The amount of mucilage in the seeds can be substantial (up to 30% in ''P. ovata'' ). Being located only in the epidermis of the testa, it mainly consists (up to 85%) of a water-soluble polysaccharide fraction (arabinoxylan) in which D-xylose is the main constituent. The backbone is a xylan polymer with 1-3 and 1-4 linkages and no apparent regularity in their distribution, with the xylose monomers substituted on C-2 or C-3 by L-arabinose, D-xylose and α-D-galacturonyl-L-rhamnose. The quality of the mucilage is evaluated by measuring its swelling index, which should exceed 9. ''P. lanceolata'' and ''P. major'' provide a similar mucilage which is rich in D-galactose and L-arabinose and contains nearly 40% uronic acids. On hydrolysis the mucilage of ''P. afra'' yields D-xylose (about 70%), L-arabinose (about 10%), α-D-galacturonyl-(1-4)-L-xylose and D-galactose; the swelling index must be at least 10. The seeds also contain 5-10% lipids with unsaturated fatty acids, sterols, 15-18% proteins, traces of cyclopentanopyridine-type alkaloids and the iridoid aucubin. An isomer of ricinoleic acid, β-hydroxyolefinic acid 9-hydroxy-cis-11-octadecenoic acid, has been found as a minor constituent (1.5%) of the seed oil of ''P. major'' .

The reticuloendothelial reticulo-endothelial system-potentiating and alkaline phosphatase-inducing activities of the mucilage from ''P. asiatica'' have been found to be markedly enhanced when the mucilage was de-O-acetylated. The deacetylated product showed considerable anti-complementary activity as well as considerable hypoglycaemic activity on administration to mice.

Leaves of ''P. major'' contain iridoids and phenols: flavonoids, phenolic acids and phenylpropanoic esters of glycosides (verbascoside, plantamajoside). The iridoid glucoside majoroside has also been isolated from ''P. major'' , along with aucubin and catalpol. ''P. lanceolata'' leaves also contain iridoids (1.9-2.4%) such as aucubin, catalpol and asperuloside, flavonoids and phenolic acids. Aucubin glycoside can be detected by thin-layer chromatography of a methanol extract. It can also be quantified by high pressure liquid chromatography. The proposed levels for the French pharmacopoeia are 0.5% for ''P. major'' and 1.0% for ''P. lanceolata'' . The content of aucubin in ''P. asiatica'' is reported in Vietnam to decrease gradually from the roots to the flowers and leaves. The drying temperature affects the content of aucubin; plant material dried at 80°C is reported to contain higher concentrations of aucubin than plant material dried at 40°C. Analysis of dried samples sold on markets in Vietnam showed that aucubin was absent, but that the allantoin content was often high (up to 80%) which makes the drug effective for the treatment of burns and stomach ulcers. The iridoids have a potential role in anti-inflammatory activity. Aucubigenin liberated from aucubin by glycosidases present possesses antibacterial activity. 3,4-Dihydroxyphenethyl alcohol-6-O-caffeoyl-β-D-glucoside, the phenylethanoid glycoside plantasioside, acteoside (verbascoside), plantaginin, plantamajoside and the phenylpropanoid glycoside hellicoside have been isolated from aerial parts of ''P. asiatica'' . Acteoside showed high inhibition of lens aldose reductase. Plantamajoside and hellicoside showed high inhibition of cyclic AMP phosphodiesterase and 5-lipoxygenase, which might have some correlation with the therapeutic effect of the herb as anti-inflammatory and anti-asthmatic. Acteoside and plantamajoside, which have also been found in ''P. lanceolata'' , showed inhibitory effects on arachidonic acid-induced ear oedema in mice. A hot-water extract of the whole plant of ''P. major'' exhibits diuretic activity and dissolves kidney stones. A chromatographic fraction of dried leaves was found to promote wound healing. Aqueous extracts of ''P. lanceolata'' showed immunomodulatory effects; in tests they stimulated the production of anti-SRBC (IgG) antibodies in mice and stimulated the release of angiogenic factors by mouse spleen cells and human mononuclear blood cells, and in vitro a ''P. lanceolata'' polysaccharide fraction showed an increase in phagocytosis of granulocytes. Liquid ''P. lanceolata'' preparations are said to have hepatoprotective (chloroform, α-amanitin) activity, and might also offer protection against adverse effects of cytostatic agents (e.g. 5-fluorouracil). In vitro experiments showed a mortality of 76% of the zooflagellate ''Giardia duodenalis'' when treated with a ''P. major'' extract.

In the United States, interplanting peach trees with ''P. lanceolata'' reduced nematode numbers ( ''Criconemella xenoplax'' ), but not to acceptable levels to justify commercial control. In tests with germinating lettuce seeds, aqueous extracts of ''P. lanceolata'' and ''P. major'' showed allelopathic activity.

Pollen, particularly that of ''P. lanceolata'' , may cause allergic reactions in sensitive persons.

The seed of flax ( ''Linum usitatissimum'' L.) also contains mucilage which can be used as "bulk laxative" just like that of ''Plantago'' seeds. All parts of some ''Malvaceae'' such as the European ''Althaea officinalis'' L. and ''Malva sylvestris'' L. contain mucilage which is used orally in the adjunctive therapy of the painful component of spasmodic colitis and for symptomatic treatment of cough, and topically as emollient and to treat itch. In India, ''Plantago'' seeds are frequently mixed with those of ''Salvia aegyptiaca'' L., which also yield copious mucilage.

Iridoid glycosides are fairly common in dicotyledonous Angiosperms. They are, for instance, present in ''Scrophulariaceae'' such as ''Verbascum'' species, which are used in phytotherapy for similar purposes as ''Plantago'' . Aucubin is also present in the genera ''Aucuba'' ( ''Cornaceae'' ) and ''Garrya'' ( ''Garryaceae'' ).

*Annual or perennial herbs up to 50(-80) cm tall, stemless or with branched stem. *Leaves in basal rosettes or opposite, with distinct, parallel veins, usually distinctly petiolate when in rosettes and without distinct petiole when inserted on stems; stipules absent. *Inflorescence a pedunculate, bracteate spike. *Flowers actinomorphic, usually bisexual, 4-merous; sepals connate at base or free, equal or nearly so, imbricate, scarious, persistent; corolla gamopetalous, usually with patent or deflexed imbricate lobes, scarious, persistent; stamens inserted on corolla tube, alternating with corolla lobes, exserted, anthers conspicuous; ovary superior, 2-4-locular, style 1 with a stout pilose stigma, protruding. *Fruit a circumscissile capsule, few- to many-seeded. *Seeds with endosperm and straight embryo; testa thin, often mucilaginous when wet. *Seedling with epigeal germination; cotyledon sessile or shortly petiolate, sheathed at base; hypocotyl elongate, epicotyl absent; first leaves alternate or opposite (in species developing stems).

''P. ovata'' and ''P. afra'' seem to be occasionally confused in the literature on cultivated ''Plantago'' in India, although they can easily be distinguished by leaves in rosettes ( ''P. ovata'' ) or on distinct, much-branched stems ( ''P. afra'' ).

In general, cool and dry weather is favourable to crops of ''P. afra'' and ''P. ovata'' ; they require dry weather from flowering until seed maturity (about 2.5 weeks). ''P. major'' is more tolerant of compacted soils than ''P. lanceolata'' , so the former appears frequently in almost pure stands on the edges of paths, whereas the latter often occurs in grasslands. ''P. major'' is more tolerant of waterlogging, whereas ''P. lanceolata'' is more drought tolerant. ''P. afra'' and ''P. ovata'' tolerate dry, sandy soils extremely well. They are grown in India on medium to poor sandy soils; however, they grow best on rich, well-drained loamy soils.

''P. major'' reproduces mainly by seed. A seed production of up to 14 000 seeds per plant has been reported for this species. ''Plantago'' may be multiplied by seed or vegetative means. For large-scale seed production of ''P. ovata'' , propagation is by seed. The seed is broadcast or drilled in rows 30 cm apart, so 6-13 kg/ha of seed is needed. ''P. lanceolata'' may also be propagated by new buds arising on the thick underground stem. The 1000-seed weight of ''P. afra'' is 1.1-1.2 g. Plant spacing in experimental plantings of ''P. afra'' in Thailand was 25 cm × 10-30 cm. Interplanting of ''P. ovata'' with poplar ( ''Populus'' spp.) has shown good results in India. Seeds may exhibit dormancy, which can be broken by several months of dry storage at room temperature or by a few weeks at 5°C. Seed 1-5 years old shows better germination rates than fresh seed. Seed has remained viable in the soil for over 60 years.

''P. lanceolata'' may serve as a host for ''Pseudomonas viridiflava'' and ''P. syrinage'' which can cause a serious bacterial disease in tomato. In India, ''P. major'' has been reported a host for ''Meloidogyne hapla'' which causes root galls in Irish potato. ''Meloidogyne'' species have also been identified from ''P. lanceolata'' . Larvae of the fruit weevil ''Naupactus xanthographus'' , a pest of several fruit trees, have been observed on ''P. major'' . ''P. ovata'' has been reported to be a host of the coriander aphid ( ''Hyadaphis coriandri'' ) which can be a pest of coriander, fennel, dill and celery in India.

The ''Plantago'' species treated here are common in anthropogenic habitats, and there is no reason to consider them as liable to genetic erosion. Except for ''P. major'' and ''P. lanceolata'' , the ''Plantago'' species highlighted here are not yet found in Malesia. This implies that the genetic variability of ''Plantago'' is limited in the region.

*Lilis Pangemanan